Step-by-step explanation:
x²-xy-xy+y²
x²+2xy+y²
hope it helps
If you take the square root of a number squared number then they cancel each other out and the number stays the same i.e. √[(4)^2] would equal 4.
In this problem the square root and numbered squared cancel out to leave the problem as -2a.
The solution of this problem is -2a
