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, ∞)
-25x is the slope
-42 is the y-intercept
Use completion of sq method
x^2+y^2+14x+10y-7=0
(x+7)^2+(y+5)^2=7+49+25
(x+7)^2+(y+5)^2=81
so centre is(-7,-5) radius is9
