Question

Factor:
4x2 - 9y2

Answer 1

4x^2 - 9y^2
= (2x)^2 - (3y)^2
= (2x-3y)(2x+3y)

Answer 2

\(\Large \color{MidnightBlue}{\Rightarrow (2x)^2 - (3y)^2 }\)

Use the difference of squares formula.
\(\Large \color{MidnightBlue}{\Rightarrow a^2 - b^2 = (a + b)(a - b) \Longleftrightarrow (2x + 3y)(2x - 3y) }\)