f(x) = - 2x + 4
To find the value of x at f(x) = -8
Substitute f(x) in the equation above by -8
-8 = -2x + 4
Subtract 4 from both sides to move 4 from the right side to the left side
-8 - 4 = -2x + 4 - 4
-12 = -2x
Divide both sides by -2 to find x
6 = x
The value of x at f(x) = -8 is 6
The first point x = 0
f(0) = -2(0) + 4
f(0) = 0 + 4
f(0) = 4
The point is (0, 4)
The second point y = 0
f(x) = 0
0 = -2x + 4
Add 2x to both sides
0 + 2x = -2x + 2x + 4
2x = 4
Divide both sides by 2
x = 2
The point is (2, 0)
at y = -8 x = 6