a(3x-2)+b(2x-3)
=3ax-2a+2bx-3b
=(3a+2b)x-5b
∵a(3x-2)+b(2x-3)=8x-7有无数个解
∴3a+2b=8,5b=7
∴a=26/15,b=7/5
∴a+b=26/15+7/5
=26/15+21/15
=47/15
=3又2/15