Solve equation

Question

W(w+2)=80

A. 0,-2 

B. -8,10

C. 8,-10

D. 3,16

Answer 1

Hi Beatriz,

 

First, multiply each term in the parenthesis by w (this is called the "distributive property")

 

w² + 2w = 80

 

("w" times "w" is w², or "w squared")

Then subtract 80 from both sides

 

w² + 2w - 80 = 0

 

Then you can factor this equation (you do this by asking yourself "what times what equals -80?"  Then you ask yourself if those two numbers add up to +2)

 

(w + 10)(w - 8) = 0

 

To find your two solutions, set each factor (the stuff in the parentheses) equal to zero, and solve using algebra.

 

w + 10 = 0  (subtract 10 from both sides of the equals sign)

w = -10

 

w - 8 = 0   (add 8 to both sides)

w = 8

Answer 2

Assuming that you mean w, not W, we have w(w+2) = 80.

 

So, w² + 2w - 80 = 0

 

      (w + 10)(w - 8) = 0

 

                              w = 8, -10