If f(x) = 3x^2 - x, find f(-2).

(i) The area of the cross section ABCDEFG is 1771.6cm³

(ii) The volume of the concrete lab is 212592 cm³

(iii) the total surface area of the concrete slab is 30284 cm²

(iv) The mass of the concrete slab is 40746.8 kg/m³.

Given, dimensions are 120 cm by 60 cm by

40 cm.

(i) area of cross section = 40 × 60 ₋ π(60 ₋10 ₋ 10)/2 . 1/2

                                     = 1771.6 cm³

(ii) the volume of the concrete slab = 40 × 60 × 120 ₋ 1/2 π((60 ₋ 10   ₋10)/2)² . 120

= 212592 cm³

(iii) The total surface area is:

=40 × 120 × 2 ₊ 60 × 120 ₊ 1771.6 × 2 ₊ 10 × 120 × 2 ₊ 1/2 π(60 ₋ 10 ₋10) × 120

= 30284 cm²

(iv) Mass of the concrete slab given density is 2300 kg/m³

Mass = Volume × density

Mass = 17.716 m³ ×  2300

         = 40746.8 kg/m³

Hence we get the mass as 40746.8 kg/m³.

Learn more about "Mensuration" here-

brainly.com/question/26398444

#SPJ10

Answer:

(i) x-intercepts: (2, 0), (6, 0)

(ii) vertex : (4, -4)

Explanation:

y = x² - 8x + 12

To find x intercepts, [set y = 0]

x-intercepts: (2, 0), (6, 0)

To find vertex:

x = -b/2a

  = -(-8)/2(1)

  = 4

y = x² - 8x + 12

  = 4² - 8(4) + 12

  = -4

Vertex : (4, -4)

Solve the equation for y=0

X inetercepts (2,0) and (6,0)

Vertex :-

x coordinate

Y coordinate

Verted at (4,-4)

Let's take this problem step by step:

What we know:

 [tex]x+y=4\\xy=-2[/tex]

Before we solve, let's do one thing that will help us out greatly later down the road:

 [tex]x+y=4\\(x+y)^2=4^2\\x^2+2xy+y^2=16\\x^2+2(xy)+y^2=16\\x^2+2(-2)+y^2=16\\x^2+4+y^2=16\\x^2+y^2=20[/tex]<--- useful equation

Let's rearrange the problem a little bit:

 [tex]x+\frac{x^3}{y^2}+\frac{y^3}{x^2} +y=\frac{x^3}{x^2} +\frac{x^3}{y^2}+\frac{y^3}{x^2}+\frac{y^3}{y^2}[/tex]

Combine fractions of common denominators:

[tex]\frac{x^3+y^3}{x^2} +\frac{x^3+y^3}{y^2} =(x^3+y^3)*(\frac{1}{x^2}+\frac{1}{y^2} )[/tex]

Now's let factor everything apart:

 [tex](x^3+y^3)=(x+y)(x^2-xy+y^2)\\\\\frac{1}{x^2}+\frac{1}{y^2} =\frac{x^2+y^2}{x^2y^2}[/tex]

Let's use what we know and our useful equation:

 [tex](x+y)*(x^2-xy+y^2)*(\frac{x^2+y^2}{x^2y^2} )\\=4*(x^2+y^2-xy)*(\frac{20}{(xy)^2} )\\=4*(20-(-2))*\frac{20}{(-2)^2} \\=4*22*5\\=440[/tex]

The value is 440

Answer: 440

Hope that helps!

#LearnwithBrainly

Answer:

B and D

Step-by-step explanation:

First take the equation and subtract 19 on both sides. You get x^2+8x-20=0

using the quadratic formula you get x= (-8 + or - root (8^2 -4(1)(-20)))/ 2(1)

simplify it and you get x= (-8 +or- 12) / 2  

Separate the equation into two and you get (-8 + 12) / 2    and (-8 - 12) / 2

first one gives: 4/2=2

second gives -20/2=-10

answer x=-10,2

Answer:

The ratio of sides of triangle = 13:14:15

perimeter = 84 CM

perimeter of a triangle = Sum of all sides

let the sides of a triangle be 13x, 14x and 15x

84 = 13x + 14x + 15x

84 = 42x

x = 2

13x = 13* 2 = 26 CM

14x = 14*2 = 28 CM

15x = 15*2 = 30 CM

The only equation that is written in descending order is

2x³+4x²-7x+5 , Option D is the correct answer.

A polynomial is a mathematical expression consisting of variables , constants and mathematical operators.

The standard form of a polynomial is

[tex]\rm a_1x^n +a_2x^{n-1}+............+a_0[/tex]

The only equation that is in its standard form or in other words

The only equation that is written in descending order is

2x³+4x²-7x+5 , Option D is the correct answer.

To know more about Polynomial

https://brainly.com/question/11536910

#SPJ1

Answer:

the cost price is Rs. 4500 and the sale price is Rs. 5040.

Step-by-step explanation:

Let the cost price of the compute be Rs. x.

The profit earned is, Rs. 540.

The profit percentage is, 12%.

The formula to compute profit is:

Profit = SP - CP

\begin{gathered}540=x[1+\frac{12}{100}]-x\\540=1.12x-x\\540=0.12x\\x=\frac{540}{0.12}\\x=4500\end{gathered}540=x[1+10012]−x540=1.12x−x540=0.12xx=0.12540x=4500

Compute the selling price as follows:

SP = CP + profit

     = 4500 + 540

     = 5040

Thus, the cost price is Rs. 4500 and the sale price is Rs. 5040.

Answer:

-12x²-25x+13

Step-by-step explanation:

First open parenthesis.

(3 − 13x − 7x²) − (5x² + 12x − 10)

3 − 13x − 7x² − 5x² - 12x + 10

Now combine like terms.

3 − 13x − 7x² − 5x² - 12x + 10=13-25x-12x²

Now put into standard form, exponents greatest to least.

-12x²-25x+13

Hope this helps!

If not, I am sorry.

Answer:-12x²-25x+13

Step-by-step explanation:

Answer:

Distance between A and C = 16km

Bearing of A from C = 257°

Step-by-step explanation:

please see photo for detailed analysis

Answer:

Option C: 41

Step-by-step explanation:

<ABD+<CBD=90

<ABD=8x+1

<CBD=6x+5

(8x+1)+(6x+5)=90

Combine like terms

(8x+6x)+(1+5)=90

14x+6=90

14x=90-6

14x=84

divide both sides by 14

x=6

Now we plug that value into <DBC = 6x+5

6(6)+5=

36+5

41

Let's take this problem step by step:

∠ABC is 90 degrees

 ⇒ made up of two angles ⇒ ∠ABD and ∠DBC

     ⇒ in mathematical equation form:

            [tex]ABD + DBC= ABC[/tex]

Since ∠ABD = 8x + 1 and ∠DBC = 6x+5

    [tex]8x + 1+6x + 5=90\\14x+6=90\\14x=84\\x=6[/tex]

Let's plug it into ∠DBC = 6x+5

  ∠DBC = 6x+5 = 6(6)+5=41

Answer: ∠DBC = 41

Hope that helps!

#LearnwithBrainly

Answer:

All answers are correct.

Step-by-step explanation:

A. 1.84 is between 1.74 and 1.84.

B. 1.84 < 1.85. Lower values go to the left.

C. 1.84 > 1.83. Higher values go to the right.

D. 1.84 is between 1.0 and 2.0.

The age of Kwaku is 8 years old , Esi is 13 years old and Kojo is 26 years old.

An equation is a statement that contains algebraic expressions equated by an equal sign with constants or other variables.

Let the age of Kwaku is x

Let the age of Esi is y

From the given data

The age of Kojo is 2y

y = x +5

Sum of their age = 47

2y = 2x +10

therefore the equation formed is

x + y +2y = 47

x + x+5 + 2x +10 = 47

4x +15 = 47

4x = 32

x = 8

y = 13

2y = 26

Therefore Kwaku is 8 years old , Esi is 13 years old and Kojo is 26 years old.

To know more about Equation

https://brainly.com/question/10413253

#SPJ1

Answer:

-10

Step-by-step explanation:

y2- y1 -7 -3

---------- ----------

x2 - x1 -6 6

Answer:

There are 8 possible answers for the value of m

Step-by-step explanation:

3025 (55^2), 3136 (56^2), 3249 (57^2)...., 3844(62^2)

The square of the numbers 55-62 could be a solution set for m.

Answer:

D. 0 < x < 20

Explanation:

Domain is in the x axis, Range lies in the y axis.

Here it is seen that function's domain lies between 0 to 20.

Here, as the circle's are open. Domain: 0 < x < 20

Additionally,

Answer:

The probability that a student earns a grade of A is 1/7.

Let E be an event and S be the sample space. The probability of E, denoted by P(E) could be computed as:

P(E) = n(E) / n(S)

As the total number of students = n(S) = 35

Students getting the grade A = n(E) = 5

So, the probability that a student earns a grade of A:

                     P(E) = n(E) / n(S)

                             = 5/35

                             = 1/7

Hence, the probability that a student earns a grade of A is 1/7.

Keywords: probability, sample space, event

Answer:

x > 9

Step-by-step explanation:

for this inequality, we want to isolate x, so that we know the inequality of x

5x + 3 > 48

     - 3      -3        {subtract 3 from both sides to get x alone}

5x > 45

/5      /5                {divide both sides by 5 to find 1x}

x > 9

So , x > 9 is the inequality in terms of x {is the solution}

hope this helps! :)

Answer:

[tex]\huge\boxed{\sf x > 9}[/tex]

Step-by-step explanation:

5x + 3 > 48

Subtract 3 to both sides

5x > 48 - 3

5x > 45

Divide 5 to both sides

x > 9

[tex]\rule[225]{225}{2}[/tex]

Answer: f(-2) = 8

Step-by-step explanation: On the graph there’s a point (-2,8), so f(-2), which just means -2’s y value on the graph, is 8.

Answer:

The dog is 16 years old.

Step-by-step explanation:

X/4 + 6 = X/8 + 8

X/4-X/8 = 8-6

0.125X = 2

X = 2/0.125

X = 16

Answer:

16 years old

Step-by-step explanation

Dividing the dog’s age by 4 and adding 6

D÷4  + 6

dividing the dog’s age by 8 and adding 8

D÷8  + 8

equating both

D÷4  + 6 = D÷8 + 8

=> D÷4 - D÷8  = 2

multiplying by 8 both sides

=> 2D - D = 16

=> D = 16

hence, the dog is 16 years old

Answer:

d=8t

Step-by-step explanation:

Answer:

3) r = 1.5

7) y = 18

11) x = -10

Step-by-step explanation:

3) Isolate the variable by dividing each side by factors that don't contain the variable.

7) Solve for y by simplifying both sides of the equation, then isolating the variable.

11) Move all terms that don't contain x to the right side and solve.

Answer:

Slope =  - 1

Step-by-step explanation:

The equation is in form [tex]y=mx+c[/tex], [tex]m[/tex] s the slope and [tex]c[/tex]  is the intercept on [tex]y[/tex] axis.

Hence, in [tex]y=-x+3[/tex] , slope is -1  and intercept on [tex]y[/tex] axis is 3.

Step-by-step explanation:

[tex]z - 6 < 3 \\ z < 3 + 6 \\ z < 9[/tex]

Hope it helps

Z – 6 < 3

Z < 3 + 6

Z < 9

Answer:

Draw a line from one point A to B into the XY line in a angle

Draw a line parallel to the lines

Point a dot in the middle and name it O

Step-by-step explanation:

Hope it helps

Answer:

x=3.5

Step-by-step explanation:

x × 2 = 7

   ÷2     ÷2

    x=3.5

Answer: x

Step-by-step explanation:

    For this equation, the variable y is dependent on the value of x. The value of y changes depending on the value of x. This means that x is the independent variable for this equation.

Answer: (2,9)

Step-by-step explanation:

It lies in the region that is shaded both red and blue (representing the fact that it satisfies both inequalities).