40% of 65
0.40(65) = 26 returned the survey. (assuming that everybody who took the survey returned it.)
Subtitute the pair (3,28) to x and y, if the result in right side is -8, then the pair is a solution to the equation
2x - y/2
= 2(3) - 28/2
= 6 - 14
= -8
The result is -8, so the pair (3,28) is a solution
Do you mean the value of y? there is no q in these equations.
C - (x-3)^2=36
If we expand (x-3)^2=36:
(x-3)(x-3)=36
x^2-3x-3x+9=36
x^2-6x+9=36
Then subtract 36
x^2-6x-27=0