What is the average rate of change?

Solve the equation for x.3(6x - 1) = 12 i've tried doing the math and i can't find out what i'm doing wrong

Bring the fraction a/a-4 to a denominator of 16-a^2

Given: ab ≅ bc and ao ≅ oc ok − angle bisector of ∠boc find: m∠aok