Solve for x 4/7+3/(x-3)=53/56

Subtract ${\displaystyle \frac{4}{7}}$ from both sides of the equation.

To write ${\displaystyle -\frac{4}{7}}$ as a fraction with a common denominator, multiply by ${\displaystyle \frac{8}{8}}$.

Write each expression with a common denominator of ${\displaystyle 56}$, by multiplying each by an appropriate factor of ${\displaystyle 1}$.

Combine the numerators over the common denominator.

Simplify the numerator.

Cancel the common factor of ${\displaystyle 21}$ and ${\displaystyle 56}$.

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

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.

The number ${\displaystyle 1}$ is not a prime number because it only has one positive factor, which is itself.

Not prime

The prime factors for ${\displaystyle 8}$ are ${\displaystyle 2\cdot 2\cdot 2}$.

The LCM of ${\displaystyle 1,8}$ is ${\displaystyle 2\cdot 2\cdot 2=8}$.

The factor for ${\displaystyle x-3}$ is ${\displaystyle x-3}$ itself.

${\displaystyle (x-3)}$ occurs ${\displaystyle 1}$ time.

The LCM of ${\displaystyle x-3}$ is the result of multiplying all factors the greatest number of times they occur in either term.

The Least Common Multiple ${\displaystyle \mathrm{LCM}}$ of some numbers is the smallest number that the numbers are factors of.

Multiply each term in ${\displaystyle \frac{3}{x-3}=\frac{3}{8}}$ by ${\displaystyle 8(x-3)}$.

Simplify the left side.

Simplify the right side.

Rewrite the equation as ${\displaystyle 3x-9=24}$.

Move all terms not containing ${\displaystyle x}$ to the right side of the equation.

Divide each term in ${\displaystyle 3x=33}$ by ${\displaystyle 3}$ and simplify.