Question

(x分之x的平方-y的平方)乘以(x的平方-2xy+y的平方分之2x)其中x=2y=1

Answer 1

(x分之x的平方-y的平方)乘以(x的平方-2xy+y的平方分之2x)其中x=2y=1

=(x^2-y^2)/x *2x/(x-y)^2

=(x+y)(x-y)/x *2x/(x-y)^2

=2(x+y)/(x-y)

=2(2+1)/(2-1)

=6