Question

已知x-3y=0,x的2次-2xy+y的2次分之2x+y乘以x-y的值

Answer 1

x-3y=x-y-2y=0 得到x-y=2y x=3y
x的2次-2xy+y的2次=(x-y)²=4y²
2x+y乘以x-y=(2x+y)(x-y)=(2x+y)·2y=8y²
所以，式子转化为4y²分之8y²=2

Answer 2

X-3Y=0
X=3Y
(2X+Y)(X-Y)/(X²-2XY+Y²)
=(2X+Y)(X-Y)/(X-Y)²
=(2X+Y)/(X-Y)
=(2*3Y+Y)/(3Y-Y)
=7Y/2Y
=7/2