Question

Use this system of equations to answer the questions that follow.

4x – 9y = 7

–2x + 3y = 4
What number would you multiply the second equation by in order to eliminate the x-terms when adding to the first equation?


What number would you multiply the second equation by in order to eliminate the y-terms when adding to the first equation?

Answer 1

to eliminate x, u would multiply second equation by 2

to eliminate y, u would multiply second equation by 3

Explanation:

Answer 2

To eliminate the x-terms, multiply the second equation by 2.

To eliminate the y-terms, multiply the second equation by 3.

Explanation:

The first step of solving by elimination requires that you eliminate either the x-terms or y-terms by making the two terms have the same coefficient, but opposite signs.

So, if you wanted to eliminate the x-terms, you could multiply the second equation so that its x term has the same coefficient as the x-term in the first equation, but with opposite signs. The x-term in the first equation is 4x. The x-term in the second equation is -2x. They already have opposite signs, so we just need the -2x to become -4x. -4x divided by -2x is 2, thus you would multiply the second equation by 2.

If you wanted to eliminate the y-terms, the process is the same. The y-term in the first equation is -9y and the y-term in the second equation is 3y. Again, they already have opposite signs, we just need 3y to become 9y. 9y divided by 3y is 3, thus you would multiply the second equation by 3.