Bro that is easy just pau
Assuming you want the range of
-4cos(2x)
the range of the cosine function is -1 to 1. When that is scaled by a factor of -4, it becomes 4 to -4.
The range of F(x) is [-4, 4] in interval notation.
_____
If you want the range of
F(x) = -4cos²(x)
that range will be -4×[0, 1] = [-4, 0].
We know that:

is an equation of a circle.
When we substitute x and y (from the pairs we have), we'll get a system of equations:

and all we have to do is solve it for a, b and r.
There will be:

From equations (II) and (III) we have:

and from (I) and (II):

Now we can easly calculate a and b:

Finally we calculate

:

And the equation of the circle is:
The answerer is combining terms in x with constants
that is, 13x + 5 ≠ 18x
13x + 5 + 17x - 4.5 + x
= (13x + 17x + x ) + 5 - 4.5 ← collecting like terms
= 31x + 0.5 ← correct simplification