Say you are trying to solve the equation and you are trying to solve for x when y=0

alright, now you have an equation, all you need to do is factor, the easiest way to do that would be by adding a number such that the left hand side becomes a perfect square, this number is b in this case is 4 (it's the coefficient of x) so solve...(remember to add to both sides)

if you would like an explanation on why this works, please tell me.

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