Question

$x–\_\_\_\_\_\_\_=15$; when $\frac{x}{2}=6$.

Answer 1

Step 1: Solve the given equation to find $x$

Let us solve,

$$\begin{gathered} \frac{x}{2}=6 \\ \Rightarrow x=6\times 2 \\ \Rightarrow x=12 \end{gathered}$$

Step 2: Fill in the required blank

We have $x–\_=15$

Now, let the required number be $y$, then

$$\begin{gathered} 12-y=15 \\ \Rightarrow -y=15-12 \\ \Rightarrow -y=3 \\ \therefore y=-3 \end{gathered}$$

Thus, the blank is $\left(-3\right)$.