[tex]4x {}^{2} - 81y {}^{2} [/tex]
Write the expressions 4 & 81 in exponential form with an exponent of 2.
[tex] = 2 {}^{2} x {}^{2} - 9 {}^{2} y {}^{2} [/tex]
Multiply the terms with equal exponents by multiplying their bases.
[tex] = (2x) {}^{2} - (9y) {}^{2} [/tex]
Using
[tex]a {}^{2} - b {}^{2} = (a - b)(a + b)[/tex]
Factor the expression.
[tex] = (2x - 9y) \times (2x + 9y)[/tex]
