Question

If x>0 and x=5y, then square root of x^2-2xy+y^2 is..

Answer 1

Substitute 5y for x and see what you get.

25y^2 -10y^2 + y^2 = 16 y^2

What is the square root of that?

It is 4y. It could also be -4y

y can be any positive number