Question 163890
3x+7y-28=0

-x+12y-5=0
-> x = 12y - 5
substitute this to Equation 1:
3*(12y - 5) + 7y - 28 = 0
<=> 36y - 15 + 7y - 28 = 0
<=> 43y = 15 + 28
<=> 43y = 43
<=> y = 1

x = 12y - 5
<=> x = 12*1 - 5
<=> x = 12 - 5
<=> x = 7

so, x = 7 and y = 1