1-（x-y)/(x-2y)+（x^2-y^2)/(x^2-4xy+4y^2)实数x,y满足|2x-y+1|+2根号下3x-2y+4=0化简求值 刚才题打错了

题目

1-（x-y)/(x-2y)+（x^2-y^2)/(x^2-4xy+4y^2)实数x,y满足|2x-y+1|+2根号下3x-2y+4=0化简求值 刚才题打错了

答案

即2x-y+1=03x-2y+4=0所以x=2,y=5所以原式=1-(x-y)/(x-2y)+(x^2-y^2)/(x-2y)^2=(x^2-4xy+4y^2-x^2+3xy-2y^2+x^2-y^2)/(x-2y)^2=(x^2-xy+y^2)/(x-2y)^2=(4-10+25)/(2-10)^2=19/64