Let's replace every copy of x with 7 and simplify.

Which is clearly false. This is probably the set of steps you followed to get "no solution".
Why is there no solution? Well let's subtract 9 from both sides to isolate the square root

Recall that the result of a square root operation is never negative. The range of
and
is the set of nonnegative numbers. There is no way we can have the left hand side result in -6
If there was a negative sign out front the square root and we have this instead

then the answer would be x = 7
Unfortunately, there isn't such a negative sign, so we stick with "no solutions".
G(x) appears to be a vertical expansion of f(x) by a factor of 3. f(x) appears to be
.. f(x) = x²
so g(x) would be
.. g(x) = 3x²
Y + 3 = 1.2(x - 0)
y + 3 = 1.2x - 0
y = 1.2x - 3
False , The cross products property