How do you evaluate this system of equations: y-2x=-5; y-x=-3?

1 Answer
Jun 14, 2017

x=2, y=-1; Ordered Pair: (2,-1)

Explanation:

  1. To solve this specific system, the easiest method is substitution.
    y-2x=-5
    y-x=-3
  2. Choose one of the equations .. I will pick y-x=-3.
  3. The objective is to get one of the variables (x or y) by itself on one side of the equation .. Pick a variable to isolate .. I will pick y.
  4. To isolate y, ADD x to both sides of the equation:
    y-x=-3
    y=-3+x
  5. Look at the OTHER equation (the one you did not choose) .. That would be y-2x=-5 for me.
    See how y is EQUAL to (-3+x) ?
    You can substitute the y in y-2x=-5 with (-3+x)
    It should look like this: (-3+x)-2x=-5
  6. SIMPLIFY! Now we only have ONE variable in the equation.
    (-3+x)-2x=-5
    -3-x=-5
    -x=-2
    x=2 [THIS IS THE ANSWER FOR X]
  7. Take one of the equations and substitute x for 2 to solve for y.
    y-2x=-5
    y-2(2)=-5
    y-4=-5
    y=-1 [THIS IS THE ANSWER FOR Y]

If your teacher wants it as (x,y), it is (2,-1).