How do you factor #y^2-49#?

1 Answer
Jul 26, 2015

Answer:

Rewrite the expression as a difference of two perfect squares.

Explanation:

You can factor the difference of two perfect squares by using the formula

#a^2 - b^2 = (a-b)(a+b)#

You already have one perfect square, #y^2#, now all you have to do is write #49# as a perfect square, too.

#49 = 7 * 7 = 7^2#

The original expression now becomes

#y^2 - 7^2 = color(green)((y+7)(y-7))#