遇到了含绝对值的函数,一般般将其写成分段函数的形式
(1)证明：∵函数f(x)=|x-2|-|x-5|
(x（2）求不等试fx≥x∧2-8x+15的解集(x<2), f(x)=-3==> x^2-8x+15<=-3==> x^2-8x+18<=0∵⊿=64-72=-8<0∴无实解(2<=x<5), f(x)=2x-7>= x^2-8x+15==> x^2-10x+22<=0==>5-√3<=x<=5+√3∴5-√3<=x<5(x>=5),f(x)=3>= x^2-8x+15==> x^2-8x+12<=0==>2<=x<=6∴5<=x<=6综上：不等式f(x)>=x^2-8x+15的解集为5-√3<=x<=6(2= x^2-8x+15==> x^2-10x+225-√3<=x不懂…(2= x^2-8x+15==> x^2-10x+225-√3开始我不太明白