Question 249935
Replace -7 for x and -4 for y, then solve.
If the answer is -7=-7, then the set is a solution.


{{{6x+7y=-7}}}
{{{6(-7)+7(-4)=-7}}}
{{{-42-28=-7}}}
{{{-70=-7}}}  <--- this is incorrect, so they are NOT a solution set for this problem.