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

Algebra ->  Exponential-and-logarithmic-functions -> SOLUTION: u − 30v = −40 −3u + 80v = 100 How do I solve the system.      Log On


   

Question 958550: u − 30v = −40
−3u + 80v = 100
How do I solve the system.
Answer by macston(5194) About Me  (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