Question

若方程组2x+3y=7,ax+(b+6y)=2无解 则a+b=?

Answer 1

y=(7-2x)/3

代入

ax+(b+6)(7-2x)/3=2

3ax+7(b+6)-2(b+6)x=6

(3a-2b-12)x=-7b-36

无解则3a-2b+12=0

3a-2b=-12

求不出a+b啊