Simplify the following expression: 2x − 8y 3x2 7y − 12x. 3x2 − 14x − y 3x2 − 10x − y 3x2 − 10x − 15y 3x2 10x − y

answer:   third option is correct.

step-by-step explanation:

since we have given that

we just need to simplify the above expression:

1) add both the expression :

2) collect the like terms :

hence, third option is correct.

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