Question

the point b is the midpoint of $overline{ac}$. find the location of a.

Explanation:

Step1: Recall mid - point formula

Let the coordinate of $A$ be $x$, the coordinate of $B=-9$ and the coordinate of $C = - 3$. The mid - point formula for a one - dimensional number line is $B=\frac{A + C}{2}$.

Step2: Substitute values into formula

We have $-9=\frac{x+( - 3)}{2}$. Multiply both sides by 2: $-9\times2=x - 3$.

Step3: Simplify the equation

$-18=x - 3$.

Step4: Solve for $x$

Add 3 to both sides: $x=-18 + 3=-15$.

Answer:

$-15$