College

4. Solve the equation:
\[ 4h + \frac{1}{3} = \frac{3}{4} \]

5. Solve the equation:
\[ \frac{1}{7}f - 5 \frac{1}{2} = \frac{9}{14} \]

7. You purchased \(\$132.49\) worth of wheels and bearings for your skateboards. The shop charges \(\$15\) per board to install them. The total cost is \(\$192.49\). Write and solve an equation to determine how many skateboards were repaired.

8. A music download service charges a flat fee each month and \(\$0.99\) per download. The total cost for downloading 27 songs this month is \(\$42.72\). Write and solve an equation to determine the flat fee.

Solve the equation and check your solution:

9. \[ -5(m + 4) = 27 \]

10. \[ -12(a - 2) = -50 \]

11. Simplify the expression:
\[ -5x - 2x + 3 \]

12. The perimeter of a triangle is 60 feet. One leg is 12 feet long. Of the two unknown sides, one of them is twice as long as the other. Find the lengths of the two unknown sides.

Answer :

Sure, let's solve each problem step-by-step:

Problem 4: Solve for [tex]\( h \)[/tex] in the equation [tex]\( 4h + \frac{1}{3} = \frac{3}{4} \)[/tex].

1. Subtract [tex]\(\frac{1}{3}\)[/tex] from both sides:
[tex]\[ 4h = \frac{3}{4} - \frac{1}{3} \][/tex]

2. Find a common denominator for [tex]\(\frac{3}{4}\)[/tex] and [tex]\(\frac{1}{3}\)[/tex], which is 12:
[tex]\[ \frac{3}{4} = \frac{9}{12}, \quad \frac{1}{3} = \frac{4}{12} \][/tex]
So,
[tex]\[ \frac{9}{12} - \frac{4}{12} = \frac{5}{12} \][/tex]

3. Divide both sides by 4:
[tex]\[ h = \frac{5}{12} \times \frac{1}{4} = \frac{5}{48} \][/tex]

Thus, [tex]\( h \approx 0.1042 \)[/tex].

Problem 5: Solve for [tex]\( f \)[/tex] in the equation [tex]\( \frac{1}{7}f - 5 \frac{1}{2} = \frac{9}{14} \)[/tex].

1. Convert [tex]\( 5 \frac{1}{2} \)[/tex] to an improper fraction:
[tex]\( 5 \frac{1}{2} = \frac{11}{2} \)[/tex]

2. Subtract [tex]\(\frac{11}{2}\)[/tex] from both sides:
[tex]\[ \frac{1}{7}f = \frac{9}{14} + \frac{11}{2} \][/tex]

3. Find a common denominator for [tex]\(\frac{9}{14}\)[/tex] and [tex]\(\frac{11}{2}\)[/tex], which is 14:
[tex]\(\frac{11}{2} \approx \frac{77}{14}\)[/tex] and then,
[tex]\[ \frac{9}{14} + \frac{77}{14} = \frac{86}{14} \approx \frac{43}{7} \][/tex]

4. Multiply both sides by 7:
[tex]\[ f = 43 \][/tex]

Problem 7: Determine how many skateboards were repaired.

1. Write the equation:
[tex]\( 15 \times n + 132.49 = 192.49 \)[/tex]

2. Subtract 132.49 from both sides:
[tex]\[ 15n = 60 \][/tex]

3. Divide by 15 to solve for [tex]\( n \)[/tex]:
[tex]\[ n = 4 \][/tex]

So, 4 skateboards were repaired.

Problem 8: Find the flat fee for the music download service.

1. Set up the equation:
[tex]\( \text{flat fee} + 0.99 \times 27 = 42.72 \)[/tex]

2. Calculate [tex]\( 0.99 \times 27 = 26.73 \)[/tex]

3. Subtract 26.73 from both sides:
[tex]\[ \text{flat fee} = 42.72 - 26.73 = 15.99 \][/tex]

Problem 9: Solve for [tex]\( m \)[/tex] in [tex]\(-5(m+4)=27\)[/tex].

1. Distribute [tex]\(-5\)[/tex]:
[tex]\(-5m - 20 = 27\)[/tex]

2. Add 20 to both sides:
[tex]\(-5m = 47\)[/tex]

3. Divide by [tex]\(-5\)[/tex]:
[tex]\[ m = -\frac{47}{5} \approx -9.4\][/tex]

Problem 10: Solve for [tex]\( a \)[/tex] in [tex]\(-12(a-2)=-50\)[/tex].

1. Distribute [tex]\(-12\)[/tex]:
[tex]\(-12a + 24 = -50\)[/tex]

2. Subtract 24 from both sides:
[tex]\(-12a = -74\)[/tex]

3. Divide by [tex]\(-12\)[/tex]:
[tex]\[ a = \frac{74}{12} \approx \frac{37}{6} \approx 6.1667 \][/tex]

Problem 11: Simplify [tex]\(-5x - 2x + 3\)[/tex].

Combine like terms:
[tex]\[ -7x + 3 \][/tex]

Problem 12: Find the lengths of the two unknown sides of the triangle.

1. Let the shorter unknown side be [tex]\( x \)[/tex], then the longer side is [tex]\( 2x \)[/tex].

2. Using the perimeter equation:
[tex]\[ 12 + x + 2x = 60 \][/tex]

3. Combine like terms:
[tex]\[ 12 + 3x = 60 \][/tex]

4. Subtract 12 from both sides:
[tex]\[ 3x = 48 \][/tex]

5. Divide by 3:
[tex]\[ x = 16 \][/tex]

So, the lengths of the unknown sides are 16 and 32 feet.