Elimination Method

L1: 3x+2y-34
L2: 5x-3y= -13

1 answer

Multiply 3 x + 2 y = - 34 by 5

15 x + 10 y = - 170

Multiply 5 x -3 y = -13 by 3

15 x - 9 y = - 39

Subtract​ the equations:

15 x + 10 y = - 170
-
15 x - 9 y = - 39
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15 x - 15 x + 10 y - ( - 9 y ) = - 170 - ( - 39 )

10 y + 9 y = - 170 + 39

19 y = - 131

y = - 131 / 19

Put this value in equation 3 x + 2 y = - 34

3 x + 2 ∙ ( - 131 / 19 ) = - 34

3 x - 262 / 19 = - 34

Add 262 / 19 to both sides

3 x = - 34 + 262 / 19

3 x = - 646 / 19 + 262 / 19

3 x = - 384 / 19

3 x = - 3 ∙ 128 / 19

Divide both sides by 3

x = - 128 / 19