D=2r
<span> diameter= 14cm
so, radius= 14/2= 7cm
</span>

Rewrite the term 

Expand each term so we have

Use the fact that 

Use the fact that
when a is an even number

Simplify


Let me know if you need any clarifications, thanks!
That would be the point (3, -1)
$10.50 because you can find 7% by multiplying the cost ($150) by 0.07 which is 7% in a decimal.
Umm I think if you calculate it it will be 129,929