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Simultaneous equations - elimi...
Solve the following pair of simultaneous equations by the elimination method
3x+4y=-1
3x+8y=4

Correct Answer

Incorrect Answer

How to get the right answer:

3x+4y=-1 (1)
3x+8y=4 (2)
Subtract (1) from (2)
(3x+8y) - (3x+4y) = 4 - (-1)
3x - 3x + 8y - 4y = 4 + 1
4y = 5
y = 5/4
Substitute this into equation (1)3x + 4*(5/4) = -1
3x + 5 = -1
3x = -6 ----> x=-2
Therefore x=-2, y=5/4.