Question

4. Sundar used linear combination to solve the system of equations shown. He did so by multiplying the first equation by 5 and the second equation by another number to eliminate the y-terms. What number did Sundar multiply the second equation by?
2x + 9 = 41
3x + 5y = 36

Answer 1

If he multiplied the first equation by 5, that would give us:

10x + 45y = 205

Now we need to get -45y to eliminate the y-terms, So we divide -45 / 5 and we get -9. So we multiply the 2nd equation by -9.

(I'm assuming the first equation is actually 2x + 9y = 41, and not 2x + 9 = 41)