Answer:
It can be factorised
Step-by-step explanation:
Given
x²y² + 36 - 4x² - 9y² ( rearranging )
x²y² - 4x² - 9y² + 36 ( factor first/second and third/fourth terms )
= x²(y² - 4) - 9(y² - 4) ← factor out (y² - 4) from each term
= (y² - 4)(x² - 9)
Both factors are a difference of squares and factor in general as
a² - b² = (a - b)(a + b)
Thus
y² - 4
= y² - 2² = (y - 2)(y + 2) , and
x² - 9
= x² - 3² = (x - 3)(x + 3)
Hence
x²y² + 36 - 4x² - 9y² = (y - 2)(y + 2)(x - 3)(x + 3)
