Substitution Method?

Question

I have 3 questions i cannot do which require me to use the substitution method.
Here they are:
3x-y=1
x+y=2

2.
y=x+1
x+y=2

3.
3x-4y=1
x+3y=-4
Thanks you very much.
If possible can you do the steps to get the answer i just cant do it i know how to do the elimination method but not this.

Answer 1

I will solve the first one for you, the process will be the same for the rest of them.

3x-y = 1
x+y = 2

Now we will substitute the value of y from the 2nd equation into the first.

y = 2-x

Substitute
3x - (2-x) = 1

Solve for x

4x = 3

x = 3/4

Put this value of x into the second equation and solve for y

3/4 + y = 2

y = 2 - 3/4

y = 5/4 and x = 3/4

Simply substitute the value of a variable from one equation into the other equation and solve.

OK?
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