Philip P. answered • 10/21/17

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^{2}+ bx + ax + ab is a quadratic and it does have only three terms. The terms ax and bx are like-terms that can be combined into (a+b)x which changes the equation into the form x^{2}+ (a + b) x + ab. Remember, a and b are just numbers. For example let a = 1 and b = 2:x

^{2}+ (a + b) x + abx

^{2}+ (1+2)x + (1)(2)x

^{2}+ 3x + 2The point is that the coefficient of the x term is equal to the sum of two number (a+b) while the constant term is equal to the product (ab) of the same two numbers. That fact allows you factor quadratics into (x+a)(x+b).