substitution method for 6x-3y=18, and y=2x-6, and show steps
I need assistance in answering the question; how would I use the substitution method to solve the system linear equation of 6x-3y=18, and y=2x-6
In the second equation, you have the value of y in terms of x. Substutute that into the first
equation in place of the y.
6x - 3y = 18
6x - 3(2x - 6) = 18
Now, you have an equation with only one unknown, x. Solve the equation.
6x - 3(2x - 6) = 18
6x - 6x + 18 = 18
18 = 18
Theoretically, this implies that you can have any value for x,
but zero is the best choice here.
Substitute zero for x into equation 1.
6x - 3y = 18
6(0) - 3y = 18
0 - 3y = 18
-3y = 18
y = 18/-3
y = -6
Re-work equation 1 so it is in slope/intercept form.
6x - 3y = 18
-3y = -6x + 18
y = 2x - 6
From this, you can see that the y-intercept is -6. This
occurs when x is zero.