Question

Select the best possible first step to solving the following system by first eliminating the x variable.

5x – 7y = –4
3x – 10y = –14

Answer 1

First you should multiply both equations so that both get 15x (the first equation by 3 and the second by 5) in order to be able to eliminate the x-variable, you should get: \[15x-21y=-12\]\[15x-50y=-70\]
Then define 15x: \[15x=21y-12 \] or \[15x=50y-70\]
Then simply substitute one of the 15 x with their 21y-12 or 50y-70.
\[21y-12=50y-70\]
\[-29y=-58\]
This should give you:
x=y=2