Question 428696: I know how to solve for X and Y in linear systems of equations using SUBSTITUTION. My teacher wants us to use ELIMINATION. The tool on this site asks me to check "Elimination or Substitution", but even when I ask it to use elimination--it solves my problem by substitution! I don't get the difference!! ex problem:
7x + 4y = 2
7x + 2y = 8
My answer is x=2 y=-3 Which I got by isolating 7x in each equation, then setting 2 equations equal to each other 2-4y = 8-2y
Answer by htmentor(1343)   (Show Source):
You can put this solution on YOUR website! 7x + 4y = 2
7x + 2y = 8
To solve by elimination, perform addition or subtraction of the two equations to eliminate one of the variables. In this case, subtract equation (2) from equation (1):
2y = -6 -> y = -3
To get x, substitute into one of the equations:
7x + 4(-3) = 2 -> 7x = 12 + 2 -> x = 2
Ans: x=2, y=-3
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