Question

if x= 3⅓+3-⅓ then find the value of 3x³+9x​

Answer 1

Answer:

$given \:x = 3\frac{1}{3} + 3 \frac{ - 1}{3}$

$= \frac{10}{3} - \frac{8}{3}$

$= \frac{2}{3}$

putting the value of x in the equation

${3x}^{3} + 9x$

$= 3( \frac{2}{3})^{3} + 9( \frac{2}{3})$

$= 3 \times \frac{8}{27} + 9 \times \frac{2}{3}$

$= \frac{8}{9} + 6$

$= \frac{8 + 54}{9} = \frac{62}{9}$

$the \: value \: of \: {x}^{3} + 9x = \frac{62}{9}$