题目: 如果4X+3Y=78,那么X+34Y=______.当Y=15时,X=______. 答案: 4X+3Y=78,两边同时除以4,得X+34Y=78÷4=732;当Y=15时,4X+3×15=78, 4X+35=78,4X+35-35=78-35, 4X÷4=1140÷4, X=11160.故答案为:732;11160.