SOLUTION: u − 30v = −40 −3u + 80v = 100 How do I solve the system.

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Question 958550: u − 30v = −40
−3u + 80v = 100
How do I solve the system.

Answer by macston(5194)   (Show Source): You can put this solution on YOUR website!
u-30v=-40 Multiply equation by 3.
3u-90v=-120
-3u+80v=100 Add these two equations.
-10v=-20 Divide by -10
v=2 ANSWER 1: v=2 Substitute this in original equation, solve for u.
u-30(v)=-40
u-30(2)=-40 Add 60 to each side
u=20 ANSWER 2: u=20
CHECK:
3u-90v=-120
3(20)-90(2)=-120
60-180=-120
-120=-120

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