Ответы и объяснения

2013-04-30T21:39:06+04:00

1) 3x+ 5 = 8x-15

-5x = -20

x = 4

2)3x+16 = 8x-9

-5x = -25

x = 5

3)4+25y = 6+24y

25y-24y = -4+6

y = 2

4)4(x-3) - 16 = 5(x-5)

4x-12-16 = 5x-25

-x = 3

x  = -3

5) 5x+27 = 4x+21

x = -6

6)4(3-2y) - 42 = 2(3+2y)

12-8y-42 = 6+4y

-12y = 36

y = -3

7)3(4x-8) = 3x-6

12x-24 = 3x-6/3

4x-8=x-2

3x = 6

x = 2

8)1-5(1,5+x) = 6-7,5x

1-7,5-5x = 6-7,5x

2,5x = 12,5

x = 5

9)3(5-x) + 13= 4(3x-8)

15-3x+13 = 12x-32

-15x = -60

x = 4

 

2013-04-30T22:57:53+04:00

1. 3x+5=8x-15
-5x+5+15=0

-5x+20=0

x=-(-20)/5
x=20/5
x=4

2. 3x+16=8x-9
-5x+25=0

x=25/5

x=5

 

3. 4+25y=6+24y
-2+25*y-24*y=0

y=2


4. 4(x-3)-16=5(x-5)
4x-28-5x+25=0

x=-3

 

5. 5x+27=4x+21

x+27-21=0

x=-6

 

6. 4(3-2y)-42=2(3+2y)

-30-8y-6-4y=0

y=-36/12

y=-3

 

7. 3(4x-8)=3x-6
9x-24+6=0

x=18/9

x=2

 

8. 1-5(1,5+x)=6-7,5x

1-7.5-5x-6+7.5x=0

x=12.5/2.5

x=5

 

9. 3(5-x)+13=4(3x-8)

28-3x-12x+32=0

x=60/15

x=4