trinomial by grouping

Question

3x^2 + 10x -8 Factor following trinomial by grouping

Answer 1

Step 1:  Multiply 3 by -8 to get -24.

 

Step 2:  Find two numbers with product of -24 and sum of 10 

 

             The numbers are 12 and -2

 

Step 3:  Rewrite 10x as 12x - 2x and factor by grouping

 

             3x² + 10x - 8 = 3x² + 12x - 2x - 8

 

                                  = 3x(x+4) - 2(x+4)

 

                                  = (x+4)(3x -2)