# How do you factor #49x^2 - 16y^2#?

##### 1 Answer

May 28, 2016

#### Answer:

(7x - 4y)(7x + 4y)

#### Explanation:

This is a

#color(blue)"difference of squares"# In general factorised as follows.

#color(red)(|bar(ul(color(white)(a/a)color(black)(a^2-b^2=(a-b)(a+b))color(white)(a/a)|)))# Note:

#49x^2=(7x)^2" and " 16y^2=(4y)^2# let a = 7x and b = 4y and substitute

#rArr49x^2-16y^2=(7x-4y)(7x+4y)#