Question

daca e raspuns foarte repede dau coroana!!​

Answer 1

Răspuns:

Explicație pas cu pas:

Answer 2

Răspuns:

2) a) 21-20:(2*3-1)=21-20:(6-1) =21-20:5 =21-4 =17

b) 36:(25-7)+2*[17-3:(2-1) =36:18 +2*(17-3:1) =2+2*(17-3) =2+2*14=2+28=30

c) (100-25:5):5-1 =(100-5):5-1 =95:5-1 =19-1 =18

d) 120:[100-(4*15+4*5)]  =120:[100-(60+20)] =120: (100-80) =120:20 =6

3) a) 2x-1 =7

2x=7+1

2x=8

x=8:2

x=4

b) 3x+2=2x+6

3x-2x=6-2

x=4

c) 2(x+1)=x+3

2x+2=x+3

2x-x=3-2

x=1

d) (2x+1):3 =5

2x+1=5*3

2x+1=15

2x=14

x=7

e) 6:(x+1) =2

x+1 =6:2

x+1=3

x=2

4)

a) 3x-1 ≤8

3x≤8+1

3x≤9

x≤3

x∈{0;1;2;3}

b) x+12 >2x+3

12-3>2x-x

9>x

x<9

x∈{0;1;2;3;4;5;6;7;8}

c) 4(2x+1)≤6x+10

8x+4≤6x+10

8x-6x≤10-4

2x≤6

x≤3 ⇒x∈{0;1;2;3}

d) 2(x-1)<x+1

2x-2<x+1

2x-x<1+2

x<3 ⇒x∈{0;1;2}

e) 3-2x>1-x

3-1>1+2x-x

2>1+x

2-1>x

1>x

x<1 ⇒x∈{0)

Explicație pas cu pas:

*-inseamna inmultire