Answer:
For no. 1:
One of the equations say that y=-7x
So plug in -7x to the other equation as y so you equation would be
-7x= -6x-7
And then, just solve for the variable:
*add -6x to both sides*:
-x= -7
*multiply both by negative one to get a positive variable*
FOR NUMBER 1, THE ANSWER IS:
x=7
Y=-7
For no. 2:
-y=x and your other equation is 3x+5y=20
Plug in x as -y:
-3y+5y=20
*simplify*
2y=20
*divide by 2 on each side to get 1 variable alone*
Y=10
FOR NUMBER 2, THE ANSWER IS:
x=-y
Y=10
