2x+3y=k (1) 3x-4y=k+11 (2) (1)×7+(2) 14x+21y+3x-4y=7k+k+11 17x+17y=8k+11 x+y=3 所以17x+17y=17×3=51 所以8k+11=51 k=5 记得采纳回答哦~
