求解一元二次方程ax~2+bx+c=0(a≠0),有直接开平方法、配方法、公式法和因式分解法等几种常用方法．下面分别举例说明,供同学们学习时参考．一、直接开平方法例1解方程x~2-8=0．解：移项,得x~2=8．两边开平方,得x=±2 2~(1/2)．所以原方程的根为x_1=2 2~(1/2),x_2=-2 2~(1/2)．评注当一元二次方程一次项系数为0时,一般用直接开平方法来解． Solve one-dimensional quadratic equation ax~2+bx+c=0(a≠0), there are several commonly used methods such as direct open-flat method, matching method, formula method and factorization method. The following are examples to illustrate, for reference when students learn. First, direct Kaiping method Example 1 Solution equation x~2-8=0. Solution: transfer item, get x~2=8. Open the square on both sides, get x = ± 2 2 ~ (1/2). So the root of the original equation is x_1=2 2~(1/2), x_2=-2 2~(1/2). Commentary When the one-time quadratic equation coefficient is 0, it is generally solved by direct open-flat method.