How do you factor 14y^2+15y-9?

1 Answer
Aug 11, 2015

color(blue)(( 7y-3) (2y+3) is the factorised form of the expression.

Explanation:

14y^2+15y−9

We can Split the Middle Term of this expression to factorise it.

In this technique, if we have to factorise an expression like ay^2 + by + c, we need to think of 2 numbers such that:

N_1*N_2 = a*c = 14*-9 = -126
and,
N_1 +N_2 = b = 15

After trying out a few numbers we get N_1 = 21 and N_2 =-6
21*(-6) = -126, and 21+(-6)= 15

14y^2+color(blue)(15y)−9 = 14y^2+color(blue)(21y -6y)−9

= 7y(2y+3) -3 (2y +3)

color(blue)(( 7y-3) (2y+3) is the factorised form of the expression.