how do u make Y the subject in 5X+3Y=7?

5x + 3y = 7
3y = 7 - 5x
y = (7 - 5x)/3

Answer: y = (7 - 5x)/3 OR y = 7/3 - 5/3x

What you need to do is isolate y by itself on the left hand side of the equation. This can be done by moving everything else to the other side. What I do is move everything, starting with whatever is furthest away from the y first.

5x + 3y = 7
3y = 7 - 5x
y = 7/3 - 5/3x

A lot of times, people like to put it into the order

y = -5/3x + 7/3

5x+3y=7 subtract 5x from each side
3y=-5x+7 divide each side by 3
y=-5/3x+7/3

5x + 3y = 7
3y = 7 - 5x
y = (7 - 5x)/3
y = -5x/3 + 7/3

3 Y = 7 - 5 X

Y = (7/3) - (5/3) X

y = (7 - 5x)/3

There you go. :)

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//

subtract both sides of the equation by 5X to separate the X from the Y side.

Now you have 3Y on the left side and 7 - 5X on the left side


If 3Y = 7 - 5X

Then Y = (1/3) of 7 - 5X

this is of course the same as Y = (7/3) - ((5X)/3)

3Y=-5X+7

...the subject?