Question 270497
i think you meant like this?
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x+y=15_x-y=-19

Since y does not contain the variable to solve for, move it to the right-hand side of the equation by subtracting y from both sides.
x=-y+15_x-y=-19

Replace all occurrences of x with the solution found by solving the last equation for x.  In this case, the value substituted is -y+15.
x=-y+15_(-y+15)-y=-19

Remove the parentheses around the expression -y+15.
x=-y+15_-y+15-y=-19

Since -y and -y are like terms, subtract y from -y to get -2y.
x=-y+15_-2y+15=-19

Since 15 does not contain the variable to solve for, move it to the right-hand side of the equation by subtracting 15 from both sides.
x=-y+15_-2y=-15-19

Subtract 19 from -15 to get -34.
x=-y+15_-2y=-34

Divide each term in the equation by -2.
x=-y+15_-(2y)/(-2)=-(34)/(-2)

Simplify the left-hand side of the equation by canceling the common terms.
x=-y+15_y=-(34)/(-2)

Simplify the right-hand side of the equation by simplifying each term.
x=-y+15_y=17

Replace all occurrences of y with the solution found by solving the last equation for y.  In this case, the value substituted is 17.
x=-(17)+15_y=17

Multiply -1 by the 17 inside the parentheses.
x=-17+15_y=17

Add 15 to -17 to get -2.
x=-2_y=17

This is the solution to the system of equations.
Answer: x=-2
Answer: y=17