If you expand the square, you have

Simplify the right hand side:

Cancel the -3x appearing on both sides:

Multiply both sides by 4:

Consider the square root of both terms (using the doubles sign):

This works out beautifully. You COULD use long division here, but since your numerator is a quadratic, your first instinct should be to try and factor it. If you factor it, it works out to be (x - 3)(x + 2). Now it just so happens that when you do that, the (x - 3) in the numerator will cancel with the (x - 3) in the denominator leaving you with one sad and lonely (x + 2) as your answer.
Answer: 137... well i think because 180-43= to 137.
Refrection of (-20, 4) across x-axis gives (-20, 4) = (-20, -4)
Refrection of (-20, 4) across y-axis gives (20, 4)
Refrection of (-20, 4) across y = -x gives (20, -4)
Refrection of (-20, 4) across y = 7 gives (20, 10)
If f(x) is an inverse of g(x),
when
f(x)=y
g(y)=x
aka
f(g(x))=x
g(f(x))=x
basically, the values should be swiched
example
f(x)=
(1,2)
(2,3)
(4,5)
then g(x)=
(2,1)
(3,2)
(5,4)