1) −3x+y=−13
4x+5y=1
−3x+y=−13( this is y)
Now it's time for you to add
−3x+y+3x=−13+3x
Next you will substitute (3x-13) for y in the equation 4x+5y=1
4x+5y=1
4x+5(3x−13)=1
19x−65=1 <<<(for this part you start to simplify)
19x−65+65=1+65
19x=66
Then you get
19x/19= 66/19
x=66/19
Now it's time for you to substitute 66/19
y=3x−13
y=3(66/19)−13
Then for y you get
y=−49/19
So the answer for number one is
x=66/19 y=49/19.
2)x−y=−4
x−y=1
First things first add y to both sides
x−y+y=−4+y
Your result is:
x=y−4
It's time to substitute
x−y=1
y−4−y=1
−4=1
What you need to do now is add
−4+4=1+4
and you get 0=5
For this problem you have no solutions.
Hope this helps