You need to use one equation in order to solve for the other. Here's an example x+y=20 x-y=10 Now, solve for one of the variables in either equation. It does not matter which. x-y=10 Add y to both sides in order to cancel it out. x=10+y Now, plug "10+y" in for the x variable in one of the first two equations in order to find y. x=y=20 The original 10+y+y=20 This is what it would look like after plugging in x. Now, combine like terms. 10+2y=20 Next, cancel out the 10 by subtracting it from both sides. 2y=10 Now cancel out the 2 by dividing each side by two. y=5 You will now plug "5" in for why in one of the original formulas. x+y=20 The original x+5=20 After plugging in "5" for y. Now cancel out the 5 by subtracting 5 from each side. x=15 Now your answer is (15,5)