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Question 565827: can you help me answer the following question and show me step by step how you got your answer. I tried solving it using a website called interactmath.com and I got all the answers wrong.
First problem: 4x-y=9, x-3y=16
Next problem: 3x+4y=5, 2x+y=1
If I can see the work I should be able to solve all the other ones in my text book. Your help is greatly appreciated.
Answer by mananth(16946)   (Show Source):
You can put this solution on YOUR website! 4 x -1 y = 9 .............1
1 x -3 y = 16 .............2
Eliminate y
multiply (1)by -3
Multiply (2) by 1
-12 x 3 y = -27
1 x -3 y = 16
Add the two equations
-11 x = -11
/ -11
x = 1
plug value of x in (1)
4 x + -1 y = 9
4 + -1 y = 9
-1 y = 9 -4
-1 y = 5
y = -5
x=1,y=-5
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3 x + 4 y = 5 .............1
2 x + 1 y = 1 .............2
Eliminate y
multiply (1)by 1
Multiply (2) by -4
3 x 4 y = 5
-8 x -4 y = -4
Add the two equations
-5 x = 1
/ -5
x = -0.20 OR -1/5
plug value of x in (1)
3 x + 4 y = 5
-0.6 + 4 y = 5
4 y = 5 + 0.6
4 y = 5.6
y = 1.40 OR 7/5
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