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2 years ago

Expand using the distributive property: 7(3a-2b) + 5(3b-4a) =

Mathematics

1 answer:

Sloan [31]2 years ago

5 0

Answer:

the answer is a+b

Step-by-step explanation:

7(3a-2b) +5(3b-4a)

21a-14b+15b-20a

a+b

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5. A rectangular pyramid measures three feet by four feet at the base, and has a height of seven feet. Find its volume.

den301095 [7]

Answer: 28 ft

Step-by-step explanation:

Multiply 3,4, and 7 to get 84 ft cubed. To find the volume of a pyramid, divide by 3 to get 28 ft.

4 0

3 years ago

Solve the equation using the quadratic formula : x^2-10x+25=18

Sever21 [200]

$x^2-10x+25=18 \\ \\x^2-10x+25-18 = 0\\ \\ x^2-10x+ 7 =0 \\ \\a=1 , b = -10 , c= 7 \\ \\ \Delta = b^{2}-4ac = (-10)^{2}-4*1*7=100-28 = 72 \\ \\\sqrt{\Delta }=\sqrt{72}= \sqrt{2*36} =\sqrt{36}*\sqrt{2} =6\sqrt{2}$

$x_{1}=\frac{-b-\sqrt{\Delta }}{2a} =\frac{10- 6\sqrt{2}}{2}=\frac{2(5-3\sqrt{2})}{2}= 5-3\sqrt{2}\\ \\x_{2}=\frac{-b+\sqrt{\Delta }}{2a} =\frac{10+ 6\sqrt{2}}{2}=\frac{2(5+3\sqrt{2})}{2}= 5+3\sqrt{2}$

$Answer : \ x= 5-3\sqrt{2} \ \ or \ \ x = 5+3\sqrt{2}$

8 0

3 years ago

Find the domain of the function expressed by the formula:

Simora [160]

Answer:

a. Domain - x= all real numbers

b. Domain - x= all real numbers except 0

c. Domain - x= all real numbers

d. Domain - x= All real numbers

Step-by-step explanation:

The domain of a function is all the possible x values. It is easy to solve for domain by graphing the function.

a graph - blue

b graph - red

c graph - green

d graph - purple

7 0

2 years ago

The time (X) to complete a standardized exam is approximately normal with a mean of 70 minutes and standard deviation of 10 minu

notka56 [123]

Answer:

77.88 minutes

Step-by-step explanation:

Given that :

Mean (m) = 70

Standard deviation (s) = 10

For 80% of student to complete the exam. In the given time

Using the formula :

Zscore = (X - mean) / standard deviation

80th percentile = 80/100 = 0.8 has a Zscore = 0.7881

0.7881 = (X - 70) /10

0.7881 * 10 = X - 70

7.881 = X - 70

7.881 + 70 = X

77.881 = X

Hence, 77.88 minutes should be given

5 0

2 years ago

What’s the answer??????

Luba_88 [7]

2x+15
Hope this helps!

5 0

2 years ago

Read 2 more answers