Question

va rog mult ex 5.Dau cornita si va rog cu calcule la fie care

Answer 1

a) [2x-7]=5
2x=5+7
2x=12
x=12:2
x=6

b)2 [2x+5]-15=3
2 [2x+5]=15+3
2 [2x+5]=18
[2x+5]=18:2
[2x+5]=9
2x=9-5
2x=4
x=4:2
x=2

Answer 2

a) |2x-7|=5
I. 2x-7=5 → 2x=5+7 → 2x=12 → x=12:2=6
II. -(2x-7)=5 → -2x+7=5 → 2x=7-5 → 2x=2 → x=2:2=1

b) I. 2(2x+5)-15=3→ 4x+10-15=3 → 4x=3+15-10 → 4x=8 → x=8:4=2
II. -2(2x+5)-15=3→ -4x-10-15=3→ -4x=3+15+10 → x=28/-4=-7

c) I. 3[2(2x-3)-9]-8=7 →
3(4x-6-9)=7+8
3(4x-6-9)=15
4x-6-9=15:3
4x-6-9=5
4x=5+9+6
4x=20
x=20:4=5
II. 3[-2(2x-3)-9]-8=7 →
3(-4x+6-9)=15
-4x+6-9=5
-4x=5+9-6
-4x=8
x=8/-4=-2

e) I. 2x+11-7=8
2x=8+7-11
2x=4
x=4:2=2
II. -(2x+11)-7=8
-2x-11=15
-2x=15+11
-2x=26
x=26/-2=-13
III. -(2x+11-7)=8
-2x-11+7=8
-2x=8-7+11
-2x=12
x=12/-2=-6
IV. -[-(2x+11)-7]=8
2x+11+7=8
2x+18=8
2x=8-18
2x=-10
x=-10/2=-5

d) I. 3[2(2x+3)+4x-9]+5= 4(x+9)+8x-16
3(4x+6+4x-9)+5=4x+36+8x-16
3(8x-3)+5=12x+20
24x-9+5=12x+20
24x-12x=20-5+9
12x=24
x=24:12=2
II. 3[-2(2x+3)+4x-9]+5= 4(x+9)+8x-16
3(-4x-6+4x-9)+5=12x+20
3(-15)+5=12x+20
-45+5=12x+20
-40=12x+20
12x=-40-20
12x=-60
x=-60/12=-5