SOLUTION: solve by substitution 5x + 3y = 8 -7x + y = 20

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Question 548129: solve by substitution
5x + 3y = 8
-7x + y = 20
Answer by mananth(16946) About Me  (Show Source):
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5 x + 3 y = 8 .............1
1 y = 20 + 7 x ---------2
/ 1 =
y = 20 + 7 x
Substitute y in (1)
5 x + 3 ( 20 + 7 x ) = 8
5 x + 60 + 21 x = 8
5 x + 21 x = 8 -60
26 x = -52
/ 26
x= -2
Plug the value of x in (1)
5 x + 3 y = 8
5 * -2 + 3 y = 8
-10 + 3 y = 8
3 y = 18
/ 3
y= 6
m.ananth@hotmail.ca
CHECK
1 y = 20 + 7 x
6 = 20 + -14