Question

All questions are about this system of equations:

{5x +18y =23
x +3y = 2.
What should you multiply the second equation by that will make the x coefficient zero when you add the two equations ?

Answer 1

if we are eliminating x, we would multiply the 2nd equation by -5

5x + 18y = 23
x + 3y = 2....multiply by -5
-----------------
5x + 18y = 23
-5x - 15y = - 10 (result of multiplying by -5)
----------------add
0 + 3y = 13.....bye-bye x :)