How to Solve Quadratic Equations Using Various Methods

Quadratic equations are algebraic mathematical problems involving unknowns. The basic form of any quadratic equation takes the form, ax^2+bx+c=0, where the value of a, is not equal to zero. You can solve quadratic equations in two main ways: by factorizing and using the quadratic formula.

Instructions

  1. Factorizing

    • 1

      Analyze the equation you are going to solve adequately. Look carefully at the coefficients of the unknown value and the constant, c. For instance in the equation 2x^2 +10x+12=0, the coefficients of the unknown are 2 and 10 while the constant is 12.

    • 2

      Simplify the coefficients by dividing them by a smaller number. In this case, since all the coefficients are divisible by 2, divide all the numbers by two including the zero. The result will produce a quadratic equation of the form x^2+5x+6=0.

    • 3

      Look for a pair of numbers that would give the coefficient of x when added together and the product of the coefficient of x^2 and the constant when multiplied. On this example, the number pair is 2 and 3.

    • 4

      Write the initial equation with the number pair you have just obtained. This equation will take the form x^2+2x+3x+6=0. Factorize the new equation into two distinct roots. In this case, the two roots are (x+2)(x+3)=0.

    • 5

      Equate both roots to zero, that is x+2=0 and x+3=0. Collecting likes terms together, the solutions for x are -2 and -3.

    Quadratic Formula

    • 6

      Analyze the equation at hand, again checking the coefficients and the constant. For this procedure, use the previous example.

    • 7

      Fix the coefficients of the unknown and the constant in the appropriate positions in the general quadratic formula equation. The general quadratic formula is x=((-b)+SQRT((b*b)-4*a*c))/(2*a) and x=((-b)-SQRT((b*b)-4*a*c))/(2*a).The equation appears to have two formulas because each quadratic equation has two roots.

    • 8

      Use a calculator to perform the calculation. Input values of a, b and c into the equations to get the answers. In this case, using the first equation, x= ((-5)+SQRT((5*5)-4*1*6))/(2*1) and you get an answer of -2. Using the second equation, x= ((-5)-SQRT ((5*5)-4*1*6))/(2*1) and you get an answer of -3. Therefore, the equation has two distinct roots: -2 and -3.

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