Recall the binomial theorem.

1. The binomial expansion of
is

Observe that


When we multiply these by
,
•
and
combine to make 
•
and
combine to make 
and the sum of these terms is

2. The binomial expansion is

We get the
term when
:

The answer is 48 degrees because you add 42 and 90 and then subtract from 180 (total degrees of a triangle)
Dont u think their should be more points for 4 hard questions
Answer:
-11x +3y + 25
Step-by-step explanation:
7-8x+4y+18-3x-y
= -8x-3x +4y-y +18+7 (putting like terms together)
= -11x +3y + 25 (Adding like terms)