Question

1)6,42+2,31b=15,66 2)54,6-(y+14)=18,73)6*(3,6x-8,7)=12,64) (a-0,95)*0,18=0,5495) (41,9-y):4,7=3,56) 12x-5x=3,1927) 7x+5x+0,28=9,18)7,7y+15,4+6,5y=65,1

Answer 1

1)
$6.42 + 2.31b = 15.66 \\ 2.31b = 15.66 - 6.42 \\ 2.31b = 9.24 \\ b = \frac{9.24}{2.31} = 4$
2)
$54.6 - (y + 14) = 18.7 \\ y + 14 = 54.6 - 18.7 \\ y + 14 = 35.9 \\ y = 35.9 - 14 = 21.9$
3)
$6 \times (3.6 x- 8.7) = 12.6 \\ 3.6x - 8.7 = \frac{12.6}{6} \\ 3.6x - 8.7 = 2.1 \\ 3.6x = 2.1 + 8.7 \\ 3.6x = 10.8 \\ x = 3$
4)
$(a - 0.95) \times 0.18 = 0.549 \\ a - 0.95 = \frac{0.549}{0.18} \\ a - 0.95 = 3.05 \\ a = 3.05 + 0.95 = 4$
5)
$(41.9 - y) \div 4.7 = 3.5 \\ 41.9 - y= 3.5 \times 4.7 \\ 41.9 - y = 16.45 \\ y = 41.9 - 16.45 = 25.45$
6)
$12x - 5x = 3.192 \\ 7x = 3.192 \\ x = \frac{3.192}{7} = 0.456$
7)
$7x + 5x + 0.28 = 9.1 \\ 12x = 9.1 - 0.28 \\ 12x = 8.82 \\ x = \frac{8.82}{12} = 0.735$
8)
$7.7y + 15.4 + 6.5y = 65.1 \\ 14.2y = 65.1 - 15.4 \\ 14.2y = 49.7 \\ y = \frac{49.7}{14.2} = 3.5$

Answer 2

1) 2.31b = 15.66 - 6.42

2.31b = 9.24

b = 4

2)54.6 - y - 14 = 18.7

y = 54.6 - 14 - 18.7

y = 21.9

3)3.6x - 8.7 = 12.6/6

3.6x = 2.1 + 8.7

x = 3

4) a - 0.95 = 0.549/0.18

a = 3.05 + 0.95

a = 4

5) 41.9 - y = 3.5*4.7

y = 41.9 - 16.45

y = 25.45

6) 7x = 3.192

x = 0.456

7) 12x = 9.1 - 0.28

x = 8.82/12

x = 0.735

8) 14.2y = 65.1 - 15.4

14.2y = 49.7

y = 3.5

Answer 3

To solve the equations, let's follow the steps for each one:

1. 6.42 + 2.31b = 15.66

Subtract 6.42 from both sides: 2.31b = 9.24

Now, divide both sides by 2.31 to isolate 'b': b = 9.24 / 2.31 b = 4

2. 54.6 - (y + 14) = 18.7

First, simplify the parentheses: 54.6 - y - 14 = 18.7

Combine like terms: 40.6 - y = 18.7

Now, isolate 'y' by subtracting 40.6 from both sides: -y = 18.7 - 40.6 -y = -21

Multiply both sides by -1 to solve for 'y': y = 21

3. 6 * (3.6x - 8.7) = 12.6

First, distribute the 6 on the left side: 21.6x - 52.2 = 12.6

Now, add 52.2 to both sides: 21.6x = 12.6 + 52.2 21.6x = 64.8

Finally, divide both sides by 21.6 to find 'x': x = 64.8 / 21.6 x = 3

4. (a - 0.95) * 0.18 = 0.549

First, distribute the 0.18 on the left side: 0.18a - 0.18 * 0.95 = 0.549

Simplify: 0.18a - 0.171 = 0.549

Now, add 0.171 to both sides: 0.18a = 0.549 + 0.171 0.18a = 0.72

Finally, divide both sides by 0.18 to find 'a': a = 0.72 / 0.18 a = 4

5. (41.9 - y) / 4.7 = 3.56

First, multiply both sides by 4.7 to get rid of the fraction: 41.9 - y = 3.56 * 4.7 41.9 - y = 16.772

Now, subtract 41.9 from both sides to solve for 'y': -y = 16.772 - 41.9 -y = -25.128

Multiply both sides by -1 to find 'y': y = 25.128

6. 12x - 5x = 3.192

Combine like terms: 7x = 3.192

Now, divide both sides by 7 to find 'x': x = 3.192 / 7 x = 0.456

7. 7x + 5x + 0.28 = 9.18

Combine like terms: 12x + 0.28 = 9.18

Now, subtract 0.28 from both sides: 12x = 9.18 - 0.28 12x = 8.9

Finally, divide both sides by 12 to find 'x': x = 8.9 / 12 x = 0.742

8. 7.7y + 15.4 + 6.5y = 65.1

Combine like terms: 14.2y + 15.4 = 65.1

Now, subtract 15.4 from both sides: 14.2y = 65.1 - 15.4 14.2y = 49.7

Finally, divide both sides by 14.2 to find 'y': y = 49.7 / 14.2 y = 3.5

So, the solutions are:

1. b = 4
2. y = 21
3. x = 3
4. a = 4
5. y = 25.128 (rounded to three decimal places)
6. x = 0.456 (rounded to three decimal places)
7. x = 0.742 (rounded to three decimal places)
8. y = 3.5