Question

Factorise x4square -81

Answer 1

Answer:

Factorise this expression using the difference of squares: 

f(x) = x⁴ + x² + 1 

f(x) = (x² + 1)² - x² 

f(x) = (x² + 1 - x)(x² + 1 + x) 

f(x) = (x² - x + 1)(x² + x + 1) 

f(x) = (x² + x + 1)(x² - x + 1)

Answer 2

4x2-81=0
4x2=81
x2=81/4
x=9/2
hope this helps