SOLUTION: solve 3x+7y=-5 x=5-9y using the substitution method

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Question 220319: solve 3x+7y=-5 x=5-9y using the substitution method
Answer by jojo14344(1513) About Me  (Show Source):
You can put this solution on YOUR website!


Given: 3x%2B7y=-5%28red%28EQN1%29%29 ; x=5-9y%28green%28EQN2%29%29

Substitute green%28EQN2%29 in red%28EQN1%29:

3%28green%285-9y%29%29%2B7y=-5
15-27y%2B7y=-5
15%2B5=27y-7y ---> 20=20y ---> cross%2820%291%2Fcross%2820%291=cross%2820%29y%2Fcross%2820%29
green%28y=1%29, subst. in green%28EQN2%29

x=5-9%28green%281%29%29=5-9
green%28x=-4%29

*The solution is (-4,1), Answer



Thank you,
Jojo