# How do you factor #2x^2+5x-30#?

##### 1 Answer

May 26, 2016

#### Explanation:

Complete the square, first premultiplying by

#8(2x^2+5x-30)#

#=16x^2+40x-240#

#=(4x)^2+2(4x)(5)-240#

#=(4x+5)^2-25-240#

#=(4x+5)^2-265#

#=(4x+5)^2-(sqrt(265)^2)#

#=((4x+5)-sqrt(265))((4x+5)+sqrt(265))#

#=(4x+5-sqrt(265))(4x+5+sqrt(265))#

Dividing both ends by

#2x^2+5x-30 = 1/8(4x+5-sqrt(265))(4x+5+sqrt(265))#