Question 1) quadratic function
This is not to be confused with the quadratic formula, which is of a similar name. A quadratic function is something like y = 5x^2+10x+17.
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Question 2) Factoring method
This is where we take something like x^2+5x+6 = 0 and turn it into (x+3)(x+2) = 0, then use the zero product property getting x+3 = 0 or x+2 = 0. This leads to x = -3 or x = -2
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Question 3) Quadratic formula
This is the fairly messy/complicated formula as shown below. It's something to either write down on a reference card or just memorize.