Solve the system by addition or substitution.?

Question

Solve the system by addition or substitution.
3x + 6y = 0
x = 2/3

Answer 1

With substitution, you just plug in 2/3 for x. You already know that x = 2/3.

So, you plug it in to get:
3(2/3) + 6y = 0
2 + 6y = 0
6y = -2
y = -1/3

So, you have x = 2/3 and y = -1/3.

If you want to do it by addition, it's a little more work, but it helps flex those algebraic muscles. Multiply the second equation by -3 and add the two equations together.

3x + 6y = 0
-3x + 0y = -2

Add them to get:
0x + 6y = -2

Solve for y:
y = -1/3

Answer 2

If x = 2/3, plug this into the first equation to get
3(2/3) + 6y = 0
2 + 6y = 0
6y = -2
y = -2/6 = -1/3

Answer 3

You change "y" for "x+a million" contained in the equation 4x-3y=0. a million). 4x - 3(x+a million) = 0 then you surely distribute. 2). 4x - 3x - 3 = 0 upload the 4x and -3x. 3). x - 3 = 0 Use the addition sources of equality. 4). x = 3 change "x" contained in the equation y = x+a million to locate "y" 5). y = 3+a million upload. 6). y = 4