Find two numbers whose product is 80 and whose sum is 18

Let X & Y be the two integers

X+Y=18      Y = 18-X

XY = 80

We can substitute 18-X for Y in the equation XY = 80

X(18-X) = 80

Distributing

18X - X2 = 80

Subtract 80 from both sides so that the equation is equal to 0

-X2 + 18X - 80 = 0

Multiply (or divide by -1 so that the leading coefficient is positive, not negative)

X2 - 18X + 80 = 0

We can factor this quadratic

(X-10)(X-8) = 0

Setting each factor equal to 0 we can solve for X.

X-10 = 0       X-8 = 0

X = 10          X = 8

The two integers are 8 and 10.

Step-by-step explanation:

The answer is C, 7.5.

This is because you know that these are the same objects, since it’s asking to find the scale factor. You are able to correlate AB to EF, and that shows a scale UP of 1.5, from 2 to 3. With this scale factor of 1.5, we know that EH will be 1.5 times bigger than AD. So 1.5 x 5 is equal to 7.5.