一、观察研究一元一次函数f(x)=kx+b(k≠0),无论k,b取何值,f(x)的图象始终与x轴只有一个交点。即f(x)有且只有一个零点。一元二次函数f(x)=ax~2+bx+c(a≠0),设Δ=b~2-4ac,当Δ>0时,一元二次函数有两个零点;当Δ=0时一元二次函数有一个零点;当Δ<0时,一元二次函数无零点。我们可以由一元一次函数和一元二次函数的图象观察出一元一次方程和一元二次方程根的个数。那么, First, the observation and research Uniform function f (x) = kx + b (k ≠ 0), regardless of k, b take any value, f (x) image always has only one intersection with the x axis. That f (x) and there is only one zero. Let Δ = b ~ 2-4ac. When Δ> 0, the quadratic function has two zero points. When Δ = 0 When a quadratic quadratic function has a zero; when Δ <0, a quadratic quadratic zero. We can observe the number of roots of a linear equation and a quadratic equation from the image of a linear function and a quadratic function. Well,