# Glencoe algebra 2 the quadratic formula and the discriminant

2. Solving Quadratic Equations by Completing the Square. For quadratic equations that cannot be solved by factorising, we use a method which can solve ALL quadratic equations called completing the square. We use this later when studying circles in plane analytic geometry.

Algebra 1 - Using the discriminant In a quadratic equation, the discriminant helps tell you the number of real solutions to a quadratic equation. The expression used to find the discriminant is the expression located under the radical in the quadratic formula.

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See Quadratic Formula for a refresher on using the formula.. In Algebra 1, you found that certain quadratic equations had negative square roots in their solutions. Upon investigation, it was discovered that these square roots were called imaginary numbers and the roots were referred to as complex roots. D=b2−4ac Discriminant formula D=22−4(1)(5) Substitute: a=1, b=2, c=5 D=−16 Evaluate D Since D<0, the quadratic equation x2+2x+5=0 has no real number solutions. If the discriminant D in the quadratic formula is negative, we cannot take its square root and get a real number. This is the reason the equation has no real number solutions. A quadratic equation is an equation of the form ax^2 + bx + c = 0. Solving such an equation means finding the x that makes the equation correct. There may be one or two solutions, and they may be integers, real numbers or complex numbers. There are several methods for solving such equations; each has its advantages and disadvantages. Dec 25, 2018 · In practice, Quadratic equation are just a step further from linear equation. We still restrict the problem to a unique unknown variable (usually called ‘x’) and add one term: x² (or x*x) .