I believe -7 + 91i. i hope this helps
All you do is plug in -7 so you get f(x)=8(-7)*15 you get -56*15 which goes to -840
Answer:

Step-by-step explanation:
Simplify the expression

Calculate the product of the coefficients:
2*5*7=70
Compute the product of the variables. Since they are all the same letter, sum their exponents:

Combine the results:

Point P is the orthocenter of the triangle.
Answer:
(g - f)(x) = 3x - 33
Step-by-step explanation:
Arrange f(x)= 2x + 13 and g(x) = 5x -20 vertically as shown below:
g(x) = 5x - 20
-f(x) = -2x - 13
----------------------
(g - f)(x) = 3x - 33