a) 2(x-1)²+3x-3 = 2(x-1)²+3(x-1)
= 2(x-1)(x-1)+3(x-1)
= (x-1)[2(x-1)+3]
= (x-1)(2x-2+3)
= (x-1)(2x+1)
b) 2x²+8x+8 = 2(x²+4x+4) = 2(x+2)²
c) x²-16+(x-4)² = x² - 4² + (x-4)²
= (x+4)(x-4) + (x-4)(x-4)
= (x-4)[(x+4)+(x-4)]
= (x-4)(2x)
d) 5x²-125 = 5(x²-25) = 5(x+5)(x-5)