# How do you solve y^2 - 9 = 0 by factoring?

Aug 16, 2015

The solutions are

 color(blue)(y=3
color(blue)(y=-3

#### Explanation:

 y^2−9=0

The expression is of the form  y^2−9=y^2-3^2

And as per property:
color(blue)(a^2-b^2=(a+b)(a-b)

Applying the same property and factorising we get:

 y^2−3^2 = color(blue)((y-3)(y+3)

Now the factors can be equated to zero to obtain solutions.

y-3=0 , color(blue)(y=3
y+3=0 , color(blue)(y=-3