Jawabanmu

2014-03-12T14:01:24+07:00
1.
x + 20 < 52 - 7x
x+7x < 52-20
8x < 32
x < 4

2.
4x-2 <2x+5
4x-2x < 5+2
2x < 7
x<3,5

3.
1/3 (y-7) > y+1
y-7 > 3(y+1)
y-7 > 3y +3
y-3y > 3+7
-2y > 10
y < -5

4.
1/3 (2y+1) <1/3 (5y-1)
2y+1 < 5y -1
2y-5y <-1-1
-3y < -2
y > 2/3
2 4 2