Part A
4x10 – 64x2
= 4x2 * x8 – 4x2 * 16
= 4x2 * (x8 – 16) by distributive property
Part B
x8 is (x4)2 and 16 = 42 so a difference of squares is seen in the parentheses. The pattern a2 – b2 = (a + b)(a – b) can be used.
4x2 * (x8 – 16)
= 4x2 * (x4 + 4) * (x4 – 4)
x4 = (x2)2 and 4 = 22 so there is another difference of squares in the last factor. Use the pattern again.
= 4x2 * (x4 + 4) * (x2 + 2) * (x2 – 2)