Question

$9x–\_\_\_\_\_\_\_\_\_=–21$has the solution $(–2)$

Answer 1

Solving for $x$:

$9x–\_\_\_\_\_\_\_\_\_=–21$has the solution $(–2)$means $x=-2$

So, Now the equation becomes $9\times (-2)-\_\_\_\_\_\_\_\_=-21$

Let the missing number be $n$

Now the equation becomes $(-18)-n=-21$

$\Rightarrow$$-n=(-21)+18$ ( Transpose $-18$to the right side and while doing so it becomes $18$)

$\Rightarrow$$-n=-3$

Or, $n=3$

Hence, the blank place will be filled with $3$