Join IDNLearn.com and become part of a knowledge-sharing community that thrives on curiosity. Discover prompt and accurate responses from our experts, ensuring you get the information you need quickly.

EXERCISE 7.1

Write an algebraic equation for each problem, then solve it.

a) The sum of 5 times a number and 3 is 43.
b) The difference between 64 and a number is equal to 48.
c) The product of a number and 12 is 108.
d) 54 subtracted from double a certain number is 12.
e) The difference between five times a number and 12 is 28.
f) The quotient of 24 and a number is 8. What is the number?

Find the value of the variable that makes these number sentences true:

a) [tex]\(15 + a = 28\)[/tex]
b) [tex]\(b - 35 = 27\)[/tex]
c) [tex]\(d \div 8 = 12\)[/tex]
d) [tex]\(3e + 14 = 26\)[/tex]
e) [tex]\(3c = 69\)[/tex]
f) [tex]\(2f - 10 = ?\)[/tex]


Sagot :

Let's solve each algebraic equation step-by-step:

### 1. The sum of 5 times a number and 3 is 43.

Form the equation:
[tex]\[ 5a + 3 = 43 \][/tex]

Subtract 3 from both sides:
[tex]\[ 5a = 40 \][/tex]

Divide both sides by 5:
[tex]\[ a = 8 \][/tex]

### 2. The difference between 64 and a number is equal to 48.

Form the equation:
[tex]\[ 64 - b = 48 \][/tex]

Subtract 64 from both sides and then simplify:
[tex]\[ -b = 48 - 64 \][/tex]
[tex]\[ -b = -16 \][/tex]

Multiply both sides by -1:
[tex]\[ b = 16 \][/tex]

### 3. The product of a number and 12 is 108.

Form the equation:
[tex]\[ 12c = 108 \][/tex]

Divide both sides by 12:
[tex]\[ c = 9 \][/tex]

### 4. 54 subtracted from double a certain number is 12.

Form the equation:
[tex]\[ 2d - 54 = 12 \][/tex]

Add 54 to both sides:
[tex]\[ 2d = 66 \][/tex]

Divide both sides by 2:
[tex]\[ d = 33 \][/tex]

### 5. The difference between five times a number and 12 is 28.

Form the equation:
[tex]\[ 5e - 12 = 28 \][/tex]

Add 12 to both sides:
[tex]\[ 5e = 40 \][/tex]

Divide both sides by 5:
[tex]\[ e = 8 \][/tex]

### 6. The quotient of 24 and a number is 8.

Form the equation:
[tex]\[ \frac{24}{f} = 8 \][/tex]

Multiply both sides by [tex]\( f \)[/tex] and then divide by 8:
[tex]\[ 24 = 8f \][/tex]
[tex]\[ f = 3 \][/tex]

### Finding the value of the variable in the following number sentences:

#### 1. [tex]\( 15 + a = 28 \)[/tex]

Subtract 15 from both sides:
[tex]\[ a = 13 \][/tex]

#### 2. [tex]\( b - 35 = 27 \)[/tex]

Add 35 to both sides:
[tex]\[ b = 62 \][/tex]

#### 3. [tex]\( d \div 8 = 12 \)[/tex]

Multiply both sides by 8:
[tex]\[ d = 96 \][/tex]

#### 4. [tex]\( 3e + 14 = 26 \)[/tex]

Subtract 14 from both sides:
[tex]\[ 3e = 12 \][/tex]

Divide both sides by 3:
[tex]\[ e = 4 \][/tex]

#### 5. [tex]\( 3c = 69 \)[/tex]

Divide both sides by 3:
[tex]\[ c = 23 \][/tex]

#### 6. [tex]\( 2f - 10 = 0 \)[/tex]

Add 10 to both sides:
[tex]\[ 2f = 10 \][/tex]

Divide both sides by 2:
[tex]\[ f = 5 \][/tex]

### Summary of Solved Values

Here are the values for each variable based on the equations:

- [tex]\( a = 8 \)[/tex]
- [tex]\( b = 16 \)[/tex]
- [tex]\( c = 9 \)[/tex]
- [tex]\( d = 33 \)[/tex]
- [tex]\( e = 8 \)[/tex]
- [tex]\( f = 3 \)[/tex]

And the values for the variables in the given number sentences:

- [tex]\( a = 13 \)[/tex]
- [tex]\( b = 62 \)[/tex]
- [tex]\( d = 96 \)[/tex]
- [tex]\( e = 4 \)[/tex]
- [tex]\( c = 23 \)[/tex]
- [tex]\( f = 5 \)[/tex]