Question 92 (xxii)
Factorise the following using the identity a2−b2=(a+b)(a−b).
16x4−81
16x4−81=(4x2)2−92=(4x2+9)(4x2−9)=(4x2+9)[(2x)2−32]=(4x2+9)(2x+3)(2x−3)
Question 92 (xxiv)
y4−81
Question 92 (v)
28ay2−175ax2
Question 92 (xix)
x4−1
Question 92 (vi)
9x2−1