Answer:
x = 3/2 or x = -4
Step-by-step explanation:
The identifiable error the students have is that before the left hand side of the equation is factorized, the right hand side value of 12 ought to be brought to the left hand side, leaving a net value of zero on the right hand side. Then whatever is factored on the left hand side is then equated to zero and then we can find the two values of x after setting each of the individual factors to zero
We proceed as follows;

Answer:
8/3 or 2.667
Step-by-step explanation:
6x+4=20
20-4= 16
6x/6=x
16/6=8/3 or 2.667
The labeled angle is what's called an inscribed angle. There's a theorem (fittingly called the inscribed angle theorem) that says the measure of this angle is half the measure of the circular arc that it subtends.
In this case, the angle is subtended by an arc measuring 180°. So
(4x + 6)° = 1/2 • 180°
4x + 6 = 90
4x = 84
x = 21