已知f(x)={f(x+2),x≤-12x=2,-1＜x＜12的x次方-4,x≥1解不等式：{x≥-1f（x）≤2“{”是大括号，_数学解答

f(x)=f(x+2),x<=-1
f(x)=2x+2,-1f(x)=2^x-4,x>=1
解不等式:
x>=-1
f(x)<=2
当x>=1
f(x)=2^x-4
2^x-4<=2
2^x<=6
xln2<=ln6
x<=log2(6)
解是:
1<=x<=log2(6)
当-1f(x)=2x+2
2x+2<=2
x<=0
解是:
-1当x=1
f(x)=f(x+2)
f(1)=f(3)=2^3-4=4>2
所以x不等于1
综上,
解是:
-1