5x+y=9 and 10x-7y=-18
The coefficients of x are 5 and 10. To apply the practice of elimination, we want only one coefficient.
Let's take the first equation...
Let's multiply both sides by 2...
Let's subtract this from the second equation...
The x is eliminated.
Let's divide both sides by -9...
A negative number divided by a negative number has a positive result...
Let's plug this into either equation to establish the value of x. I randomly select the second...
Let's add 28 to both sides...
Let's divide both sides by 10...
Let's plug both values into the first equation to verify results...