Answer: x = 1, y = 3.
Explanation:
For substitution, you take the value of one variable, either x or y, and replace that variable with the equation it is equivalent to.
For simplicity, I'll substitute the y- variable. We know y has the same value as 3x, so we can replace the y-value in equation 1 with 3x:
y = -x + 4, y = 3x;
3x = -x + 4
Now simplify to find the value of x:
3x = -x + 4 = 4x = 4 = 4(/4)x = 4(/4) = x = 1
So we know x = 1, now we use this x-value to find y. You can plug x into either equation to get y.
y = -(1) + 4 = 3
or
y = 3(1) = 3
So x = 1 and y = 3.