Answers

2014-07-14T14:28:46+08:00
12-4x=0 is not a quadratic equation
(with-8) (w+5) is quadratic equation 
3x(x-2)= -7 is a quadratic equation
25-r2=4r is a quadratic equation

Note: in order to know if an equation i a quadratic equation, evaluate first the equation the look if the highest exponent is two

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