math help on hw?

Question

substistuion solve for x and y
5x-3y=1
7x-y=-5


5x+2y=-21
-2x+y=3

Answer 1

first one...
make it so its 7x+5=y
plug in y... 5x-3(7x+5)=1
5x-21x-15=1
-16x=16
x=-1
plug in x in either problems
7(-1)-y=-5
-7-y=-5
-y=2
y=-2
to check, plug in for both
5(-1)-3(-2)=1 -5+6=1 Correct
7(-1)-(-2)=-5 -7+2=-5 correct

second one...
make it so that its y=2x+3
then put it 5x+2(2x+3)=-21
then 9x+6=-21
9x=-27
x=-3
then plug in x for either problem
15+2y=-21
2y=-6
y=-3
check..
5(-3)+2(-3)=-21 -15+ -6 = -21 check
-2(-3)+(-3)=3 6-3=3 check

Answer 2

5x-3y=1
5*2-3*3=1?
10-9+1

7x-y=-5
7*3-26=5?
21-26=5

Wait, I did those wrong didn't I? Sorry! This might slightly help though.

Answer 3

for the first question. the answer is x=7 and y=2
the second the answer is x= 2 and y=6

YOUR WELCOME@