You can put this solution on YOUR website! Check which terms of the equation do not have L in them. L only occurs to the first power (exponent 1), so you want all terms of L on one side, and all other terms on the other side; and then you have one or two further steps.
Solve for L: , as given.
Symmetric Property;
Additive Inverse of 2WH;
Reverse of Distributive Property to get a factor of L;
Multiplicative Inverse Property, for the binomial factor on L.
That is a list of properties to use. Please try to manage the actual steps.
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