Question

What is x+y=7 and x-y=-3 using the elimination method

Answer 1

Step-by-step explanation:

First, line them up vertically.

x + y = 7

x - y = -3

Next add vertically.

x + x = 2x

y + (-y) = y - y = 0y

7 + (-3) = 7 - 3 = 4

Your equation should now read,

2x = 4

Divide both sides by 2 to solve for x

2x = 4

2 2

———-

x = 2

Lastly plug in 2 for x to solve for y. (It doesn’t matter which equation you use)

(2) + y = 7

-2 -2

y = 5

Answer 2

x = 2

y = 5

Step-by-step explanation:

x + y = 7; x − y = −3

Solve x+y=7 for x

x+y=7

x+y+−y=7+−y (Add -y to both sides)

x=−y+7

Step: Substitute−y+7 for x in x−y=−3:

x−y=−3

−y+7−y=−3

−2y+7=−3(Simplify both sides of the equation)

−2y+7+−7=−3+−7 (Add -7 to both sides)

−2y=−10

-2y/-2 = -10/-2

(Divide both sides by -2)

y=5

Step: Substitute 5 for y in x=−y+7:

x=−y+7

x=−5+7

x=2 (Simplify both sides of the equation)