If 5x-3y=8 and x=7y/5 then y= ?

2009-01-31 6:53 am

回答 (13)

2009-01-31 7:10 am
✔ 最佳答案
5x-3y=8 equation 1
x=7y/5 equation 2

substitute x=7y/5 to 5x-3y=8

5(7y/5)-3y=8
35y/5-3y=8
7y-3y=8
4y=8
y=2 answer//
2016-11-13 6:53 pm
Multiplying 2x+3y=8 by potential of 5 we get 10x+15y=40 Multiplying 5x-y=3 by potential of two we get 10x-2y=6 Subtracting the 2nd from the 1st we get 10x+15y-(10x-2y)=40-6 10x+15y-10x+2y=34 17y=34 y=(34/17)=2 putting fee of y in 2x+3y=8 2x+(3*2)=8 2x+6=8 2x=2 x=a million
2009-01-31 9:00 am
5x - 3y = 8 (solve by using substitution)
x = 7y/5

5x - 3y = 8
5(7y/5) - 3y = 8
7y - 3y = 8
4y = 8
y = 8/4
y = 2

∴ y = 2
2009-01-31 8:49 am
5x - 3y = 8
5 (7y / 5) - 3y = 8
7y - 3y = 8
4y = 8
y = 2

Thanks for the two points, sharaont.
2009-01-31 7:06 am
5(7y/5)-3y=8
5 get cancelled each other so
7y-3y=8
you added 3y to 8 so
7y=8+3y
then divided by 7 so
y= (8+3y)/7
i think..i hope hehe
2009-01-31 7:01 am
5x-3y=8
x=7y/5

Sub x=7y/5 into 5x-3y=8
5(7y/5) - 3y = 8
7y-3y=8
4y=8
y=2
2009-01-31 7:01 am
If 5x-3y=8 and x=7y/5 then y=
5(7y/5) - 3y = 8
7y - 3y = 8
4y = 8
y = 8/4 = 2
2009-01-31 7:00 am
5(7y/5)-3y=8
7y-3y=8
4y=8
y=2

You need to substitute 7y/5 for x and multiply it by 5 before continuing with anything.
2009-01-31 6:59 am
7y - 3y = 8
4y = 8
y = 2
2009-01-31 6:58 am
5(7y/5) - 3y = 8
7y - 3y = 8
4y = 8
y = 2


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