Answer:
x = 3
Explanation:
Since both have f(x), the substitution method can be used.
1. f(x) = -3x - 1
2. f(x) = -10
Therefore,
-3x - 1 = -10
Flip to positive to calculate more easily since all are negative (although, this is optional.)
3x + 1 = 10
3x + 1 - 1 = 10 - 1 (to make one side x and other side number)
3x = 9
x = 3
Hope this helped! ^^