Solve the equation by factoring.

Question

8x² + 26x + 7 = -8

 

How do I solve this step by step?

Answer 1

8x² + 26x + 15 = 0

 

Step 1:  multiply 8 by 15 to get 120

 

Step 2:  find 2 numbers with product 120 and sum 26 (they are 20 and 6)

 

Step 3:  rewrite 26x as 20x + 6x and factor by  grouping

 

             8x² + 20x + 6x + 15 = 0

 

             4x(2x+5) + 3(2x+5) = 0

 

             (2x+5)(4x+3) = 0

 

   2x+5 = 0 or 4x+3 = 0

 

   x = -5/2 or -3/4