How do I get Mathematica to simplify my expression? [closed]

Laplacian[x/(x^2 + y^2), {x, y}]
(8 x^3)/(x^2 + y^2)^3 + (8 x y^2)/(x^2 + y^2)^3 - (8 x)/(x^2 + y^2)^2
% === 0

False

Since we have $$\frac{8x^3}{(x^2+y^2)^3}+\frac{8xy^2}{(x^2+y^2)^3}-\frac{8x}{(x^2+y^2)^2}$$

we can turn the third term to $\frac{(x^2+y^2)8x}{(x^2+y^2)(x^2+y^2)^2}$, and simplify this whole expression to get zero.

How can I get Mathematica to do this?

closed as off-topic by Bob Hanlon, m_goldberg, J. M. will be back soon♦Mar 19 '17 at 5:23

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• You have to simplify the expression by using Simplify command. – Anjan Kumar Mar 19 '17 at 3:24
• Checking for equality doesn't simplify expressions to the full. For example, x-x===0 returns True, whereas, 1/(1 + a) - a/(a + a^2) === 0 returns False. Therefore, it is better to explicitly use Simplify. – Anjan Kumar Mar 19 '17 at 3:37