Multiply both sides of the first equation by

:

This is quadratic in

; to make this clear, substitute

. Then

One of these solutions for

is negative. But, if

is real, then

is always supposed to be positive, so we can throw out the negative root, leaving

.
We actually don't have to solve for

exactly. We can just rewrite the next two equations in terms of

.


Since

, we get

Hello there.
<span>Question: What is 2c+7=21 please help
Answer: Solve the equation:
Subtract 7 from both sides:
21 - 7 = 14
2c = 14.
Divide both sides by 2:
14/2 = 7
c = 7.
</span>Hope This Helps You!
Good Luck Studying ^-^
7x+2 is the equation because each pizza cost 7 dollars and the y-intercept is at 2
X=-12.52
The reason why is because to get x by itself we have to get rid of 15.09, so we subtract 15.09 from both sides and 2.57-15.09=-12.52
Hope this helps!