22+-+Sec.+9.2

=Solving Quadratic Equation=

A quadratic equation in x is an equation that can be written in the standard form. In this form, a is the leading coefficient Equation:ax^2 + bx + c=0

Solving x^2 = d by finding square roots.. 1.) If d is positive, then x^2 = d has two solutions: x = +/- sq.root d 2.) The equation x^2 = 0 has one solution: x = 0 3.) If d is negative, then x^2 = d has no solution.

Example for Solving Quadratic Equations: the equation x^2 = 4 has two solutions: x = +/-2

Example for transforming before finding square roots: Solve: 3x^2 - 48 = 0 Solution: 3x^2 - 48 = 0 3x^2 = 48 x^2 = 16 x = +/-sq.root16 x = +/-4 The solutions are both negative and positive four.

Examples: Evaluate the expression: Solve for x: 4x^2 - 100 = 0 4x^2 = 100 x^2 = 25 x = +/-5

Practice Problems

1) Solving Quadratic Equation

81x^2 - 5 = 20

2) Solve: 7x 2 -49=0

3) Solve:

2x 2 -162 =0