规定运算*,使得x*y=axy除以4x+5y,且1*2=1,2*3?

问题描述:

规定运算*,使得x*y=axy除以4x+5y,且1*2=1,2*3?

将X=1,Y=2代入,得A=7
则2*3=7X2X3/4X2+5X3=42/23