1.
f(x) + g(x)
Since f(x) = -5x - 4, we can substitute -5x - 4 in for f(x)
f(x) + g(x) = (-5x - 4) + g(x)
Since g(x) = 6x - 7, we can substitute 6x - 7 in for g(x)
f(x) + g(x) = (-5x - 4) + (6x - 7)
f(x) + g(x) = -5x - 4 + 6x - 7
Combine like terms.
f(x) + g(x) = x - 11
2.
f(x) - g(x)
Since f(x) = 3x + 2, we can substitute 3x + 2 in for f(x)
f(x) - g(x) = (3x + 2) - g(x)
Since g(x) = 6x - 7, we can substitute 6x - 7 in for g(x)
f(x) - g(x) = (3x + 2) - (6x - 7)
Distribute the -1 to the terms in parenthesees.
f(x) - g(x) = 3x + 2 - 6x + 7
Combine like terms.
f(x) - g(x) = -3x + 9