F(x) = x²-4x-5, quadratic function,
Domain (the values if x) is all real numbers.
To find range we should draw a graph or to write an equation in vertex form.
f(x) = x²-4x+4-4-5
f(x) = (x-2)²-9
Point (-2,-9) is the vertex of the parabola, and it is a minimum because a parabola has positive sign in front of x², so it is looking up. Minimum value of y =-9
Range(the values of y) is [-9, ∞)
The inverse of this function is f^-1(x)=x/9
The playground is a square, so there will be a right triangle formed by diagonal and two sides. So sides length²*2=diagonal length². So the side length is 38.9 meter.
