Verified answer

(a+b)³=a³+3a²b+3ab²+b³

(2+4х)³

a=2

b=4x

(2+4х)³=2³+3·2²·(4x)+3·2·(4x)²+(4x)³=8+48x+96x²+64x³

(z+2x)³

a=z

b=2x

(z+2x)³=z³+3·z²·(2x)+3·z·(2x)²+(2x)³=z³+6z²x+12zx²+8x³

(5+z)³

a=5

b=z

(5+z)³=5³+3·5²z+3·5·z²+z³=125+75z+15z²+z³