Pre-Algebra Examples

$\frac{2}{5 x} + \frac{1}{4} = \frac{39}{10 x} - \frac{1}{3}$

Step 1

Move all terms not containing $x$ to the right side of the equation.

Tap for more steps...

Step 1.1

Subtract $\frac{1}{4}$ from both sides of the equation.

$\frac{2}{5 x} = \frac{39}{10 x} - \frac{1}{3} - \frac{1}{4}$

Step 1.2

To write $- \frac{1}{3}$ as a fraction with a common denominator, multiply by $\frac{4}{4}$ .

$\frac{2}{5 x} = \frac{39}{10 x} - \frac{1}{3} \cdot \frac{4}{4} - \frac{1}{4}$

Step 1.3

To write $- \frac{1}{4}$ as a fraction with a common denominator, multiply by $\frac{3}{3}$ .

$\frac{2}{5 x} = \frac{39}{10 x} - \frac{1}{3} \cdot \frac{4}{4} - \frac{1}{4} \cdot \frac{3}{3}$

Step 1.4

Write each expression with a common denominator of $12$ , by multiplying each by an appropriate factor of $1$ .

Tap for more steps...

Step 1.4.1

Multiply $\frac{1}{3}$ by $\frac{4}{4}$ .

$\frac{2}{5 x} = \frac{39}{10 x} - \frac{4}{3 \cdot 4} - \frac{1}{4} \cdot \frac{3}{3}$

Step 1.4.2

Multiply $3$ by $4$ .

$\frac{2}{5 x} = \frac{39}{10 x} - \frac{4}{12} - \frac{1}{4} \cdot \frac{3}{3}$

Step 1.4.3

Multiply $\frac{1}{4}$ by $\frac{3}{3}$ .

$\frac{2}{5 x} = \frac{39}{10 x} - \frac{4}{12} - \frac{3}{4 \cdot 3}$

Step 1.4.4

Multiply $4$ by $3$ .

$\frac{2}{5 x} = \frac{39}{10 x} - \frac{4}{12} - \frac{3}{12}$

Step 1.5

Combine the numerators over the common denominator.

$\frac{2}{5 x} = \frac{39}{10 x} + \frac{- 4 - 3}{12}$

Step 1.6

Subtract $3$ from $- 4$ .

$\frac{2}{5 x} = \frac{39}{10 x} + \frac{- 7}{12}$

Step 1.7

Move the negative in front of the fraction.

$\frac{2}{5 x} = \frac{39}{10 x} - \frac{7}{12}$

Step 2

Find the LCD of the terms in the equation.

Tap for more steps...

Step 2.1

Finding the LCD of a list of values is the same as finding the LCM of the denominators of those values.

$5 x, 10 x, 12$

Step 2.2

Since $5 x, 10 x, 12$ contains both numbers and variables, there are two steps to find the LCM. Find LCM for the numeric part $5, 10, 12$ then find LCM for the variable part $x^{1}, x^{1}$ .

Step 2.3

The LCM is the smallest positive number that all of the numbers divide into evenly.

1. List the prime factors of each number.

2. Multiply each factor the greatest number of times it occurs in either number.

Step 2.4

Since $5$ has no factors besides $1$ and $5$ .

$5$ is a prime number

Step 2.5

$10$ has factors of $2$ and $5$ .

$2 \cdot 5$

Step 2.6

The prime factors for $12$ are $2 \cdot 2 \cdot 3$ .

Tap for more steps...

Step 2.6.1

$12$ has factors of $2$ and $6$ .

$2 \cdot 6$

Step 2.6.2

$6$ has factors of $2$ and $3$ .

$2 \cdot 2 \cdot 3$

Step 2.7

The LCM of $5, 10, 12$ is the result of multiplying all prime factors the greatest number of times they occur in either number.

$2 \cdot 2 \cdot 3 \cdot 5$

Step 2.8

Multiply $2 \cdot 2 \cdot 3 \cdot 5$ .

Tap for more steps...

Step 2.8.1

Multiply $2$ by $2$ .

$4 \cdot 3 \cdot 5$

Step 2.8.2

Multiply $4$ by $3$ .

$12 \cdot 5$

Step 2.8.3

Multiply $12$ by $5$ .

$60$

Step 2.9

The factor for $x^{1}$ is $x$ itself.

$x^{1} = x$

$x$ occurs $1$ time.

Step 2.10

The LCM of $x^{1}, x^{1}$ is the result of multiplying all prime factors the greatest number of times they occur in either term.

$x$

Step 2.11

The LCM for $5 x, 10 x, 12$ is the numeric part $60$ multiplied by the variable part.

$60 x$

Step 3

Multiply each term in $\frac{2}{5 x} = \frac{39}{10 x} - \frac{7}{12}$ by $60 x$ to eliminate the fractions.

Tap for more steps...

Step 3.1

Multiply each term in $\frac{2}{5 x} = \frac{39}{10 x} - \frac{7}{12}$ by $60 x$ .

$\frac{2}{5 x} (60 x) = \frac{39}{10 x} (60 x) - \frac{7}{12} (60 x)$

Step 3.2

Simplify the left side.

Tap for more steps...

Step 3.2.1

Rewrite using the commutative property of multiplication.

$60 \frac{2}{5 x} x = \frac{39}{10 x} (60 x) - \frac{7}{12} (60 x)$

Step 3.2.2

Cancel the common factor of $5$ .

Tap for more steps...

Step 3.2.2.1

Factor $5$ out of $60$ .

$5 (12) \frac{2}{5 x} x = \frac{39}{10 x} (60 x) - \frac{7}{12} (60 x)$

Step 3.2.2.2

Factor $5$ out of $5 x$ .

$5 (12) \frac{2}{5 (x)} x = \frac{39}{10 x} (60 x) - \frac{7}{12} (60 x)$

Step 3.2.2.3

Cancel the common factor.

$5 \cdot 12 \frac{2}{5 x} x = \frac{39}{10 x} (60 x) - \frac{7}{12} (60 x)$

Step 3.2.2.4

Rewrite the expression.

$12 \frac{2}{x} x = \frac{39}{10 x} (60 x) - \frac{7}{12} (60 x)$

Step 3.2.3

Combine $12$ and $\frac{2}{x}$ .

$\frac{12 \cdot 2}{x} x = \frac{39}{10 x} (60 x) - \frac{7}{12} (60 x)$

Step 3.2.4

Multiply $12$ by $2$ .

$\frac{24}{x} x = \frac{39}{10 x} (60 x) - \frac{7}{12} (60 x)$

Step 3.2.5

Cancel the common factor of $x$ .

Tap for more steps...

Step 3.2.5.1

Cancel the common factor.

$\frac{24}{x} x = \frac{39}{10 x} (60 x) - \frac{7}{12} (60 x)$

Step 3.2.5.2

Rewrite the expression.

$24 = \frac{39}{10 x} (60 x) - \frac{7}{12} (60 x)$

Step 3.3

Simplify the right side.

Tap for more steps...

Step 3.3.1

Simplify each term.

Tap for more steps...

Step 3.3.1.1

Rewrite using the commutative property of multiplication.

$24 = 60 \frac{39}{10 x} x - \frac{7}{12} (60 x)$

Step 3.3.1.2

Cancel the common factor of $10$ .

Tap for more steps...

Step 3.3.1.2.1

Factor $10$ out of $60$ .

$24 = 10 (6) \frac{39}{10 x} x - \frac{7}{12} (60 x)$

Step 3.3.1.2.2

Factor $10$ out of $10 x$ .

$24 = 10 (6) \frac{39}{10 (x)} x - \frac{7}{12} (60 x)$

Step 3.3.1.2.3

Cancel the common factor.

$24 = 10 \cdot 6 \frac{39}{10 x} x - \frac{7}{12} (60 x)$

Step 3.3.1.2.4

Rewrite the expression.

$24 = 6 \frac{39}{x} x - \frac{7}{12} (60 x)$

Step 3.3.1.3

Combine $6$ and $\frac{39}{x}$ .

$24 = \frac{6 \cdot 39}{x} x - \frac{7}{12} (60 x)$

Step 3.3.1.4

Multiply $6$ by $39$ .

$24 = \frac{234}{x} x - \frac{7}{12} (60 x)$

Step 3.3.1.5

Cancel the common factor of $x$ .

Tap for more steps...

Step 3.3.1.5.1

Cancel the common factor.

$24 = \frac{234}{x} x - \frac{7}{12} (60 x)$

Step 3.3.1.5.2

Rewrite the expression.

$24 = 234 - \frac{7}{12} (60 x)$

Step 3.3.1.6

Cancel the common factor of $12$ .

Tap for more steps...

Step 3.3.1.6.1

Move the leading negative in $- \frac{7}{12}$ into the numerator.

$24 = 234 + \frac{- 7}{12} (60 x)$

Step 3.3.1.6.2

Factor $12$ out of $60 x$ .

$24 = 234 + \frac{- 7}{12} (12 (5 x))$

Step 3.3.1.6.3

Cancel the common factor.

$24 = 234 + \frac{- 7}{12} (12 (5 x))$

Step 3.3.1.6.4

Rewrite the expression.

$24 = 234 - 7 (5 x)$

Step 3.3.1.7

Multiply $5$ by $- 7$ .

$24 = 234 - 35 x$

Step 4

Solve the equation.

Tap for more steps...

Step 4.1

Rewrite the equation as $234 - 35 x = 24$ .

$234 - 35 x = 24$

Step 4.2

Move all terms not containing $x$ to the right side of the equation.

Tap for more steps...

Step 4.2.1

Subtract $234$ from both sides of the equation.

$- 35 x = 24 - 234$

Step 4.2.2

Subtract $234$ from $24$ .

$- 35 x = - 210$

Step 4.3

Divide each term in $- 35 x = - 210$ by $- 35$ and simplify.

Tap for more steps...

Step 4.3.1

Divide each term in $- 35 x = - 210$ by $- 35$ .

$\frac{- 35 x}{- 35} = \frac{- 210}{- 35}$

Step 4.3.2

Simplify the left side.

Tap for more steps...

Step 4.3.2.1

Cancel the common factor of $- 35$ .

Tap for more steps...

Step 4.3.2.1.1

Cancel the common factor.

$\frac{- 35 x}{- 35} = \frac{- 210}{- 35}$

Step 4.3.2.1.2

Divide $x$ by $1$ .

$x = \frac{- 210}{- 35}$

Step 4.3.3

Simplify the right side.

Tap for more steps...

Step 4.3.3.1

Divide $- 210$ by $- 35$ .

$x = 6$