Question

已知函数 f（x）= |x-3| + |x+1| . （1）作出y= f（x）的图象；（2）解不等式 f（x）<=6

能帮忙画张图那最好不过啦！ 麻烦咯.. 0。 0

Answer 1

1.  x<-1     f(x)=-2x+2

-1<=x<=3   f(x)=4

x>3           f(x)=2x-2

2. f(x)<=6

 x<-1     -2x+2<=6          x>=-2

-2<=x<-1

-1<=x<=3   f(x)=4<6    成立

x>3           f(x)=2x-2<=6    x<=4

3<x<=4

  解不等式 f（x）<=6  的解集为 【-2,4】