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y= 2x-7

5x-2y =15

 May 17, 2017
edited by CheeseMilk23  May 17, 2017
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Solve the following system:
{y = 2 x - 7 | (equation 1)
5 x - 2 y = 15 | (equation 2)
Express the system in standard form:
{-(2 x) + y = -7 | (equation 1)
5 x - 2 y = 15 | (equation 2)
Swap equation 1 with equation 2:
{5 x - 2 y = 15 | (equation 1)
-(2 x) + y = -7 | (equation 2)
Add 2/5 × (equation 1) to equation 2:
{5 x - 2 y = 15 | (equation 1)
0 x+y/5 = -1 | (equation 2)
Multiply equation 2 by 5:
{5 x - 2 y = 15 | (equation 1)
0 x+y = -5 | (equation 2)
Add 2 × (equation 2) to equation 1:
{5 x+0 y = 5 | (equation 1)
0 x+y = -5 | (equation 2)
Divide equation 1 by 5:
{x+0 y = 1 | (equation 1)
0 x+y = -5 | (equation 2)
Collect results:
Answer: | x = 1           and                y = -5

 May 17, 2017

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