Answer:
(-1, 2) and (4, -8)
Explanation:
You want the ordered pairs (x, f(x)) that satisfy both equations ...
- f(x) = x² -5x -4
- f(x) = -2x
Solution
Equating the two expressions for f(x), we have ...
x² -5x -4 = -2x
x² -3x -4 = 0
(x -4)(x +1) = 0
x = 4 or -1
Corresponding values of f(x) are ...
f(x) = -2{4, -1} = {-8, 2}
Ordered pair solutions are ...
(x, f(x)) = (-1, 2) and (4, -8)