Question

What is the value of x????

Answer 1

If QR is a median, then:

$\dfrac{NO+MP}{2}=QR$

We have NO = 30, MP = 9x - 42 and QR = x + 15. Substitute:

$\dfrac{30+9x-42}{2}=x+15\qquad\text{multiply both sides by 2}\\\\9x-12=2x+30\qquad\text{add 12 to both sides}\\\\9x=2x+42\qquad\text{subtract 2x from both sides}\\\\7x=42\qquad\text{divide both sides by 7}\\\\\boxed{x=6}$

Answer: A. 6