Question

Choose the correct answer :$\frac{3\mathrm{x}}{7}-\frac{\mathrm{x}}{5}$

• A. $\mathrm{x}$
• B. $\frac{3{\mathrm{x}}^2}{35}$
• C. $\frac{8\mathrm{x}}{35}$
• D. $\frac{15}{7}$

Answer 1

The correct option is C

$\frac{8\mathrm{x}}{35}$

Justification of answer:

To simplify :$\frac{3\mathrm{x}}{7}-\frac{\mathrm{x}}{5}$

Convert the given above algebraic fractions into like fractions by obtaining L.C.M of their denominators, we get

L.C.M of $7$and $5=35$

$\frac{3\mathrm{x}}{7}=\frac{3\mathrm{x}\times 5}{7\times 5}=\frac{15\mathrm{x}}{35}$

$\frac{\mathrm{x}}{5}=\frac{\mathrm{x}\times 7}{5\times 7}=\frac{7\mathrm{x}}{35}$

$\frac{3\mathrm{x}}{7}-\frac{\mathrm{x}}{5}$ $=\frac{15\mathrm{x}}{35}-\frac{7\mathrm{x}}{35}$

$=\frac{15\mathrm{x}-7\mathrm{x}}{35}$

$=\frac{8\mathrm{x}}{35}$

Thus, option C is the correct answer