The first step to solve a quadratic equation that's set to zero is to factor the quadratic equation:

b² - 7b + 6 = 0
(b - 1)(b - 6) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (b - 1) or (b - 6) must equal zero:

If (b - 1) = 0, b must equal 1
If (b - 6) = 0, b must equal 6

So the solution is that b = 1 or 6

A line on the coordinate grid can be defined by a slope-intercept equation: y = mx + b. For a given value of x, the value of y can be determined given the slope (m) and y-intercept (b) of the line. The slope of a line is change in y over change in x, \({\Delta y \over \Delta x}\), and the y-intercept is the y-coordinate where the line crosses the vertical y-axis.

The circumference of a circle is the distance around its perimeter and equals π (approx. 3.14159) x diameter: c = π d. The area of a circle is π x (radius)² : a = π r².

The entire length of this line is represented by AD which is AB + BD:

AD = AB + BD

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.