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 slope of this line is the change in y divided by the change in x. The endpoints of this line segment are at (-2, 9) and (2, -3) so the slope becomes:

To solve this equation, repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the equal sign and the answer on the other.

-9z + 6 = \( \frac{z}{-8} \)
-8 x (-9z + 6) = z
(-8 x -9z) + (-8 x 6) = z
72z - 48 = z
72z - 48 - z = 0
72z - z = 48
71z = 48
z = \( \frac{48}{71} \)
z = \(\frac{48}{71}\)

To solve this equation, repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the < sign and the answer on the other.

-7y - 3 < 4 - y
-7y < 4 - y + 3
-7y + y < 4 + 3
-6y < 7
y < \( \frac{7}{-6} \)
y < -1\(\frac{1}{6}\)

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.