Use substitution to solve the system of
equations: 5x + 5y = -30
2x - y = 15

x = 3, y = - 9

Step-by-step explanation:

5x + 5y = - 30 (1)

2x - y = 15

-y = 15 - 2x

y = 2x - 15 (2)

From equations (1) & (2)

5x + 5(2x - 15) = - 30

5x + 10x - 75 = - 30

15x = 75 - 30

15x = 45

x = 45/15

x = 3

Plug x = 3 in equation (2)

y = 2*3 - 15

y = 6 - 15

y = - 9

Therefore,

x = 3, y = - 9

or

(x, y) = (3, - 9)

(f - g)(x) = 5x^3 - 3

step-by-step explanation:

rearrange these functions vertically, with like terms in separate columns:

f(x) = 5x^3 - 2

g(x) =         +1

now subtract, column by column:

(f - g)(x) = 5x^3 - 3