14 chia hêt cho 2x+3
=>2x+3 thuộc Ư (14)
=>Ư (14)={1;2;7;14}
ta có
2x+3 | 1 | 2 | 3 | 14 |
x | X | X | 0 | X |
vậy x=0
219-7(x+1)=100
7(x+1)=219-100
7(x+1)=119
x+1 =119:7
x+1 =17
x =17-1
x =16
1) [2.(70-x)+23.32]:2=46
2.(70-x)+8.9=92
2.(70-x)+72=92
2.(70-x)=20
70-x=10
x=60
2) 6x-39=5628:28
6x-39=201
6x=240
x=40
3)2x-138=23.32
2x-138=8.9
2x-138=72
2x=210
x=105
4)219-7(x+1)=100
7(x+1)=119
x+1=17
x=16
5)14 chia het cho (2x+3)
=> (2x+3) thuoc U(14)={1;-1;2;-2;7;-7;14;-14}
TH1: 2x+3=1
2x=-2
x=-1
TH2: 2x+3=-1
2x=-4
x=-2
TH3: 2x+3=2
2x=-1
x= -1/2
TH4: 2x+3=-2
2x=-5
x=-5/2
TH5: 2x+3=7
2x=4
x=2
TH6: 2x+3=-7
2x=-10
x= -5
TH7: 2x+3=14
2x=11
x=11/2
TH8: 2x+3=-14
2x=-17
x=-17/2
Vay x thuoc {-1; -2; -1/2; -5/2; 2; -5; 11/2; -17/2}
6)2.(x-8)=22
x-8=2
x=10