Question #600cc

2 Answers
Feb 13, 2018

(x5)(x5)(x5)=x315x2+75x125

Explanation:

First, Let's Use the formula

(ab)(ab)(ab)=(ab)3=a33ba2+3ab2b3

Then,Subsutite a=xandb=5,so

(x5)3=x3(3)(5)x2+3(x)(52)53
=x315x2+75x125

Feb 13, 2018

x315x2+75x125

Explanation:

Start by expanding the first two terms. You may have learned the FOIL method, where you multiply First, Outer, Inner, then Last terms. Here it is with the first two:
(x5)(x5)
First: xx=x2
Outer: x5=5x
Inner: 5x=5x
Last: 55=25

Now add the like terms together.
x25x5x+25
x210x+25

Now multiply that trinomial by the final binomial:
x2x=x3
x25=5x2
10xx=10x2
10x5=50x
25x=25x
255=125

Again, add all like terms together to get your final answer.
x35x210x2+50x+25x125

x315x2+75x125