y=3x-1
5x-y=5

how do I do this the easy way?:confused:

If you just add the left sides of the two equations and the right sides, you're almost home. That is:

Equation 1: y = 3x-1
Equation 2: 5x-y = 5.

Add them:

y+5x-y = 3x-1+5

Notice the y terms cancel out, leaving a single equation with x as the only unknowm. So now you can solve for x. Once you have x, substitute its value into either equation 1 or 2 and solve for y.

You'd want to eliminate one of them, the y looks easy to eliminate because you have an equation with only y on one side. So you'd then get to:

5x-3x-1=5

Solve to find x, then put the value of x into an equation (I recommend the easy one) to find y.

Ta da.

Hope it helped

Sleepy, have some coffee. This post is almost a year old.

y=3x-1
5x-y=5
equation 1; y=3x-1
equation 2 ; 5x-y=5
=>5x=5+y
=>x=(5+y)/5 -> equation 2
by substituting the value of y and x on equation 2
you will get the 'y'
therefore,5*(5+y/5)-3*(5+y/5)-1=5
=>5+y(-15+3y)/5-1=5
=>y-15+3y-1=5-5
=>y+3y=0+15+1
=>4y=16
=>y=4

Samsounak - this post is over three years old, and unfortunately you got the wrong answer. If you put your value for y back into the original equation you'll find that it doesn't work. Your error starts with the substitution you made here:

therefore,5*(5+y/5)-3*(5+y/5)-1=5

That should be a +1, not a negative 1. The answer you should get is y = 5 and x = 2.

y=3x-1 --- 1
5x-y=5 --- 2
putting Y in eq. 2
5x-(3x-1)=5
2x=4
x=2
putting value of X in eq.1
Y=3*2-1
Y=6-1
Y=5
X=2,Y=5

Quote:

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Originally Posted by prateek_55

prateek_99 does not find this helpful : cudnt understand d concept

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This is uncalled for. ebaines did understand the concept and was actually pointing out that samsounak was wrong and if you read the previous posts, he already posted the steps to follow to solve the problem.

Lastly, this thread is over 3 years old and has spread enough trouble around.

THREAD CLOSED