Answer
The given statement is false.
Work Step by Step
In the synthetic division, the divisor must be in the form of $x-a$ which is a linear expression. Where,$x$ is a variable and $a$ is constant. The coefficient of the variable must be $1$.
Consider an example:
$\left( 3{{t}^{4}}+5{{t}^{3}}-8{{t}^{2}}-13t+2 \right)\div \left( {{t}^{2}}-5 \right)$
So, for this expression, the divisor $\left( {{t}^{2}}-5 \right)$ is not in the form of $x-a$.
Hence, synthetic division cannot be used. This expression is solved by long division.
So, long division can be used where synthetic division cannot be used but not vice-versa.
Therefore, the given statement is false.