6.
a)
2x+11 >= x+8
2x-x >= 8-11
x >= -3
x € { -3 ,-2, -1 ,0 , 1 ,2 ..... }
b)
2x-3 <=3x+1
2x-3x <= 1+3
-x <= 4
x >= -4
x € {-4,-3,-2,....}
c)
4x+10 >3 (x+2)
4x+10 > 3x+3×2
4x+10 > 3x +6
4x-3x >6-10
x > -4
x € {-3, -2,-1,0,1,2,.....}
d)
2 (x+5) <=5x+19
2x+2×5 <= 5x+19
2x+10 <= 5x+19
2x-5x <= 19-10
-3x >= 9
3x >= -9
x >= (-9):3
x >= -3
atentie sa vezi ca inversez La un moment dat si semnul <= in semnul >= ok?
x € {-3,-2,-1,0,1,2,3,....}
e)
7x+11 > 2 (2x-5)
7x+11 >2×2x -2×5
7x+11 > 4x -10
7x-4x > (-10) - 11
3x > -21
x > (-21):3
x > -7
x € {-6,-5,-4,-3,-2, -1.0, 1 ......}
f)
3 (2x-1) >=5 (x-1)
3×2x -3×1 >= 5x-5×1
6x-3 >= 5x-5
6x-5x >= -5+3
x >= -2
x € { -2 ,-1, 0, 1 ,2 ....}
