90-1,2,3,5,6,9,10,15,18,30,
45,90
1)0.7x-3.5=x-0.1
0.8x-x=-0.1+3.5
0.6x=3.4
x=5.6
2)1.5x-9=1.4x+7
1.5x-1.4x=7+9
0.1x=16
x=160
3)9-x=1.2x-2
-x-1.2x=-2-9
-2.2x=-11
x=5
4)8-1.6x=6-1.5x
-1.6x+1.5x=6-8
-0.1x=-2
x=20
6^x≤6^1
(6 > 1) x ≤ 1
x-1 < 0
x < 0
3^x≤3^1
(3 > 1) x ≤1
(1/3)^x ≥3
3^(-x) ≥ 3
(3 > 1) -x ≥3
x ≤ - 3
3^x ≥ 3^1
(3 > 1) x ≥ 1