could someone help me with this?

Question

Factor the polynomial completely.

2x²+7x−60=

 

how can i factor 2 out if 2 doesn't go into 7? i'm so confused 

Answer 1

2x² + 7x − 60

 

Use the "ac" method where a = 2 and c = -60.  a*c = 2*(-60) = -120.  You want factors of -120 that add up to +7.  Answer = 15*(-8) = 120, 15+(-8) = 7.  Now factor by grouping:

 

2x² + 15x - 8x - 60

 

x(2x+15) - 4(2x+15)

 

(x-4)(2x+15)