Simplify the expression

$(36 p^2 + 49 q^2)(6p + 7q)(6p - 7q)$

$1296 p^4 - 2401 q^4$

Given,

(36 p² + 49 q²) (6p + 7q) (6p − 7q)

We know that,

a² - b² = (a + b)(a - b)

So,

 (36p² + 49q²) (6p + 7q) (6p − 7q)

= (36p² + 49q²) (36p² − 49q²)

Let 36p² = m and

 49q² = n

So, (36p² + 49q²) (36p² − 49q²) = (a + b)(a - b)

= a² - b²

a² - b² = (36p²)² − (49q²)²

= 1296p⁴ - 2401q⁴