(2x-y)/(x+y)=2两边同时乘以22*(2x-y)/(x+y)=2*2把2乘以进去,有(4x-2y)/(x+y)=4(2x-y)/(x+y)=2两边取倒数,有(x+y)/(2x-y)=1/2两边乘以44(x+y)/(2x-y)=2把4乘进括号里(4x+4y)/(2x-y)=2那么(4x-2y)/(x+y)-(4x+4y)/(2x-...