X=-9
-x=9 so x=-9 since you inverse the sign
No they are not equivalent and if you are trying to get a mixed number try dividing
X+3y=7
x-3y=1
add them together
x+3y=7
<u>x-3y=1 +
</u>2x+0y=8
2x=8
divide 2
x=4
subsitute
x+3y=7
4+3y=7
subtract 4
3y=3
divid 3
y=1
x=4
y=1
answer is A
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