Answer:
[tex] {5x}^{2} + 6x = - 8[/tex]
Step-by-step explanation:
This question is asking you to insert two equations, f(x) and g(x), into the equation g(x) - f(x). This will lead to the equation below.
[tex] { - 12x}^{2} - 15x + 7 - ({ - 7)x}^{2} + 9x - 15[/tex]
Now we can solve for the equation.
[tex] { - 5x}^{2} - 6x - 8 = 0 \\ {5x}^{2} + 6x = - 8[/tex]