Question

Using the elimination method how do I find x and y for the following problem:

3x+5y=-1
x + 5y = 4

Answer 1

x is equal to -3, and y is equal to eight fifths, or 1.6

Explanation:

Solving by elimination means to add or subtract one of the equations from the other, eliminating one of their common terms.

Because both of the provided ones have the term 5y (and no other y terms), let's use subtraction:

3x + 5y = -1

- ( x + 5y = 5 )

2x + 0 = -6

Which we can solve pretty quick:

2x = -6

x = -3

We can now solve either of the original equations for y:

x + 5y = 5

-3 + 5y = 5

5y = 8

y = 8/5, or 1.6

To make sure we're correct, let's test our results in the other equation:

3x + 5y = -1

3 × -3 + 5 × 8/5 = -1

-9 + 8 = -1

-1 = -1

So we're good!