Which equation does the graph of the systems of equations solve?
2 linear graphs. they intersect at 1,2
x + 4 = −2x − 1
x + 2 = −3x + 1
−x + 3 = 3x − 1
x + 3 = 2x − 1

The correct option is 3.

Step-by-step explanation:

It is given that two linear graphs intersect at (1,2). It means the solution of both lines is x=1 and y=2.

The equation which is satisfied by x=1 will be the required equation.

In option (1),

Substitute x=1.

Option 1 is incorrect.

In option (2),

Substitute x=1.

Option 2 is incorrect.

In option (3),

Substitute x=1.

Option 3 is correct.

In option (1),

Substitute x=1.

Option 4 is incorrect.

Therefore the correct option is 3.

answer: 12

step-by-step explanation:

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