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Arturiano [62]
3 years ago
15

If a=1 and b=3; then a3 b2- 2a

Mathematics
1 answer:
Delicious77 [7]3 years ago
3 0

a=1

b=3


a^3*b^2-2a=1^3 * 3^2 -2*1 = 1*9 -2 = 9-2= 7


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Claire's music playlist contains songs she bought and songs her mother bought. The ratio of her songs to her mother's songs is 3
Vsevolod [243]

Answer:

B.

Step-by-step explanation:

The ratio of Claire's songs to her mother's songs = 3 : 2

A.

3 : 2 = 3/2

9 : 6 = 9/6 = 3/2

12 : 10 = 12/10 = 6/5

B.

3 : 2 = 3/2

6 : 4 = 6/4 = 3/2

15 : 10 = 15/10 = 3/2

C.

3 : 2 = 3/2

4 : 3 = 4/3

5 : 4 = 5/4

D.

3 : 2 = 3/2

4 : 6 = 4/6 = 2/3

20 : 30 = 20/30 = 2/3

The table which shows the correct ratio and two equivalent ratios is B

7 0
3 years ago
7 – Зу = 20
nata0808 [166]

Answer:

x=1/15 y = -4 1/3

Step-by-step explanation:

First combine like terms.

-3y = 13

y= -13/3

y= -4 1/3

Substitute for y in next equation

-4 1/3 = 5x - 4

5x = 4 1/3 - 4

5x = 4 1/3 - 4

5x = 1/3

x = 1/3 divided by 5

Since fractions can't be divided, multiply by the inverse

x = 1/3 times 1/5 = 1/15

5 0
3 years ago
The table shows the viscosity of an oil as a function of temperature. Identify a quadratic model for the viscosity, given the te
777dan777 [17]

Answer:

The viscosity at 140°C is predicted to be 7.2

Step-by-step explanation:

The function that model the relationship between viscosity and temperature = Quadratic model

The general form of a quadratic equation is y = a·x² + b·x + c

Therefore, we have;

When y = 10.8, x = 110, which gives;

10.8 = a·110² + b·110 + c = 12100·a + 110·b + c

10.8 = 12100·a + 110·b + c

When y =8.2, x = 130

8.2 = a· 130² + b· 130 + c = 16900·a + 130·b + c

8.2 = 16900·a + 130·b + c

When y = 160, x = 5.8

5.8 = a·160² + b·160 + c = 25600·a + 160·b + c

5.8 = 25600·a + 160·b + c

The three equations above can be listed as follows;

10.8 = 12100·a + 110·b + c

8.2 = 16900·a + 130·b + c

5.8 = 25600·a + 160·b + c

Solving using matrices gives;

\begin{bmatrix}12100 & 110 & 1\\ 16900 & 130 & 1\\ 25600 & 160 & 1\end{bmatrix} \begin{bmatrix}a\\ b\\ c\end{bmatrix} = \begin{bmatrix}10.8\\ 8.2\\ 5.8\end{bmatrix}

\begin{bmatrix}a\\ b\\ c\end{bmatrix} = -\dfrac{1}{3000}\begin{bmatrix}3 & -5 & 2\\ -867 & 1350 & -480\\ 62400 & -88000 & 28600\end{vmatrix} \begin{bmatrix}10.8\\ 8.2\\ 5.8\end{bmatrix}

From which we have;

a = 0.001, b = -0.37, c = 39.4

Substituting gives;

y = 0.001·x² - 0.37·x + 39.4

When x = 140

y = 0.962·140² - 0.37·140 + 39.4= 7.2

The viscosity at 140°C = 7.2.

8 0
3 years ago
Sides AB and DC of the rectangle are increased in length by 50% and sides AD and BC are decreased in length by 50%. What is the
emmainna [20.7K]

The percentage of change in the area of the rectangle is -25% ⇒ B

Step-by-step explanation:

The given is:

  • Sides AB and DC of the rectangle are increased in length by 50%
  • Sides AD and BC are decreased in length by 50%

We need to find the percentage change in the <em>AREA</em> of the rectangle

Assume that the length of AB ans DC is x units, and the length of AD and BC is y units

∵ The length of the sides AB and DC increased by 50%

∵ The length of AB and CD = x

- That means x will increase by 50% of x

∵ 50% of x = (50 ÷ 100) × x = 0.5 x

∴ The length is increased by 0.5 x

∴ The new length of AB and CD = x + 0.5 x = 1.5 x units

∵ The length of the sides BC and AD decreased by 50%

∵ The length of BC and AD = y

- That means y will decrease by 50% of y

∵ 50% of y = (50 ÷ 100) × y = 0.5 y

∴ The length is decreased by 0.5 y

∴ The new length of BC and AD = y - 0.5 y = 0.5 y units

∵ The area before the change = x × y = xy units²

∵ The area after the change = 1.5 x × 0.5 y = 0.75 xy units²

∵ The new area is less than the old area

∴ The area is decreased

- To find the the percentage of change in the area subtract the

   new area from the old area and divide the difference by the

    old area and then multiply the quotient by 100%

∴ The percentage of the change = \frac{xy-0.75xy}{xy} × 100%

∴ The percentage of the change = \frac{0.25xy}{xy} × 100%

∴ The percentage of the change = 0.25 × 100%

∴ The percentage of the change = 25%

∴ The area of the rectangle is decreased by 25% ⇒ (-25%)

The percentage of change in the area of the rectangle is -25%

Learn more:

You can learn more about the percentage in brainly.com/question/12960754

#LearnwithBrainly

7 0
4 years ago
The total use of electricity in the United States was 0.4 trillion kilowatt-hours in 1950 and about 2.8 trillion kilowatt-hours
lora16 [44]

Answer: 7

Step-by-step explanation:

Scientific notation is a method that is used in very large numbers or when we've very small numbers. The number given will be multiplied by its power of 10. In this case,

2.8 trillion = 2,800,000,000,000

= 2.8 × 10^12

0.4 trillion = 400,000,000,000

= 4 × 10^11

Therefore, the times more electricity was there in 1999 than 1950 will be:

= (2.8 × 10^12) / (4 × × 10^11)

= (2.8/4) / (10^12 - 11)

= 0.7 × 10

= 7 times

There were 7 times more electricity that was there in 1999 than 1950.

3 0
3 years ago
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