Solve 5/3c-12-3/7c-28

$$\frac { 5 } { 3 c - 12 } - \frac { 3 } { 7 c - 28 }$$

Evaluate

$$\frac{26}{21\left(c-4\right)}$$

Short Solution Steps

Factor 3c-12. Factor 7c-28.

$$\frac{5}{3\left(c-4\right)}-\frac{3}{7\left(c-4\right)}$$

To add or subtract expressions, expand them to make their denominators the same. Least common multiple of 3\left(c-4\right) and 7\left(c-4\right) is 21\left(c-4\right). Multiply \frac{5}{3\left(c-4\right)} times \frac{7}{7}. Multiply \frac{3}{7\left(c-4\right)} times \frac{3}{3}.

$$\frac{5\times 7}{21\left(c-4\right)}-\frac{3\times 3}{21\left(c-4\right)}$$

Since \frac{5\times 7}{21\left(c-4\right)} and \frac{3\times 3}{21\left(c-4\right)} have the same denominator, subtract them by subtracting their numerators.

$$\frac{5\times 7-3\times 3}{21\left(c-4\right)}$$

Do the multiplications in 5\times 7-3\times 3.

$$\frac{35-9}{21\left(c-4\right)}$$

Do the calculations in 35-9.

$$\frac{26}{21\left(c-4\right)}$$

Expand 21\left(c-4\right).

$$\frac{26}{21c-84}$$

Factor

$$\frac{26}{21\left(c-4\right)}$$