Verified answer

a)    ....=(x+2)(x+2)=(x+2)²

б)   .....=(x-5)(x-5)=(x-5)²

в)   ....=(x+1)(x+1)(x+1)=(x+1)³

г)   ....=x³-3*4x²+3*16x - 4³=x³-3*(2x)²+3x*4² - 4³=(x-4)³