ROVIKULY 2.09 : (x – 5)^3 = ? (problem with solution)

Buy the whole book.

——————————-
Transcript:
Please calculate
x minus 5, all cubed.

FORMULA:
a minus b, all cubed
equals
a cubed
minus 3 a squared b
plus 3 a b squared
minus b cubed.

SOLUTION:
x minus 5, all cubed
equals
x cubed
minus 3 times x squared times 5
plus 3 times x times 5 squared
minus 5 cubed.

Which equals
x cubed
minus 3 times 5 times x squared
plus 3 times 25 times x
minus 125.

Which equals
x cubed
minus 15 x squared
plus 75 x
minus 125

ANSWER:
x minus 5, all cubed
equals
x cubed
minus 15 x squared
plus 75 x
minus 125.
——————————-