Question

solve for x if m is a midpoint.
a 12 m 3x - 9 b

Explanation:

Step1: Use mid - point property

If M is the mid - point of AB, then AM = MB. So, we set up the equation 12=3x - 9.

Step2: Add 9 to both sides

Adding 9 to both sides of the equation 12 = 3x - 9 gives 12+9=3x - 9+9, which simplifies to 21 = 3x.

Step3: Divide both sides by 3

Dividing both sides of 21 = 3x by 3, we get $\frac{21}{3}=\frac{3x}{3}$, so x = 7.

Answer:

x = 7