Determine which of the following expressions requires combining like terms before it is considered to be in its simplest form. select all situations that apply. 4x + 3y - 7x a2 + a2 - b 5y - x a2 + a2b -5w2 + y - 4w2 - 8y

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