# How do you factor 49 - 4x^2?

This expression can be written as ${7}^{2} - {\left(2 x\right)}^{2}$
color(blue)(a^2 - b^2 = (a+b)(a-b)
Hence 7^2 - (2x)^2 = color(green)((7+2x)(7-2x)