quadratic equation in one variable

例句：

1. 1.The quadratic equation 2x^2 + 3x - 5 = 0 has two real roots.
   这个二次方程 2x^2 + 3x - 5 = 0 有两个实根。
2. 2.The quadratic equation x^2 - 4x + 4 = 0 has two real roots.
   这个二次方程 x^2 - 4x + 4 = 0 有两个实根。
3. 3.Solving the quadratic equation, we find that the roots are 2 and 4.
   解这个二次方程，我们发现根是2和4。