Explain this and what method? Is it linear combos or some sort of GCF finding

just subtracting the expression for revenue from the expression for cost

Step-by-step explanation:

  2x^3 + 30x - 130

-  2x^3 - 3x - 520

(subtracting means adding the opposite)

2x^3 - 2x^3 = 0

30x - (-3x) = 33x

-130 - (-520) = 390

well there are two answers for that.

1: you need 120 ones then that will equal up to 120.

2: you could also do one 100 and 2 tens.

those are the answers that i have thought of.

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18