已知-x+2y=5,那么5(x-2y)^2-3(x-2y)-60的值为?

来源:学生作业帮助网 编辑:六六作业网 时间:2024/05/14 19:31:39
已知-x+2y=5,那么5(x-2y)^2-3(x-2y)-60的值为?已知-x+2y=5,那么5(x-2y)^2-3(x-2y)-60的值为?已知-x+2y=5,那么5(x-2y)^2-3(x-2y

已知-x+2y=5,那么5(x-2y)^2-3(x-2y)-60的值为?
已知-x+2y=5,那么5(x-2y)^2-3(x-2y)-60的值为?

已知-x+2y=5,那么5(x-2y)^2-3(x-2y)-60的值为?
80
x-2y=-5 5(-5)^2-3(-5)-60=125+15-60=80

-x+2y=5 x-2y=-5
5(x-2y)^2-3(x-2y)-60=5x(-5)²-3x(-5)-60=80

由-x+2y=5,得-(x-2y)=5, 得x-2y=-5
题目就转换为:5×(-5)**2-3×(-5)-60=5*25-(-15)-60=80