Height: width
4:3 = 24:x
x = 18
The frame will be 18 inches wide.
Put the values of x to the equations of the functions:
1. f(9) → x = 9; f(x) = -3x + 10
f(9) = -3(9) + 10 = -27 + 10 = -17
2. f(-2) → x = -2; f(x) = 4x - 1
f(-2) = 4(-2) - 1 = -8 - 1 = -9
3. f(-5) → x = -5; f(x) = -2x + 8
f(-5) = -2(-5) + 8 = 10 + 8 = 18
The second equation because they all have a common factor of 3. You can get x by itself. However, with the first one, you'll end up with fractions instead.