The first step to solve a quadratic expression that's not set to zero is to solve the equation so that it is set to zero:

b² - 6b - 4 = -4b + 4
b² - 6b - 4 - 4 = -4b
b² - 6b + 4b - 8 = 0
b² - 2b - 8 = 0

Next, factor the quadratic equation:

b² - 2b - 8 = 0
(b + 2)(b - 4) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (b + 2) or (b - 4) must equal zero:

If (b + 2) = 0, b must equal -2
If (b - 4) = 0, b must equal 4

So the solution is that b = -2 or 4

Angles around a line add up to 180°. Angles around a point add up to 360°. When two lines intersect, adjacent angles are supplementary (they add up to 180°) and angles across from either other are vertical (they're equal).

A right angle measures 90 degrees and is the intersection of two perpendicular lines. In diagrams, a right angle is indicated by a small box completing a square with the perpendicular lines.

To multiply binomials, use the FOIL method. FOIL stands for First, Outside, Inside, Last and refers to the position of each term in the parentheses:

(y + 2)(y + 6)
(y x y) + (y x 6) + (2 x y) + (2 x 6)
y² + 6y + 2y + 12
y² + 8y + 12

A circle is a figure in which each point around its perimeter is an equal distance from the center. The radius of a circle is the distance between the center and any point along its perimeter. A chord is a line segment that connects any two points along its perimeter. The diameter of a circle is the length of a chord that passes through the center of the circle and equals twice the circle's radius (2r).