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 volume of a cube is height x length x width:

v = h x l x w
v = 9 x 3 x 5
v = 135

An isosceles triangle has two sides of equal length. An equilateral triangle has three sides of equal length. In a right triangle, two sides meet at a right angle.

The slope-intercept equation for a line is y = mx + b where m is the slope and b is the y-intercept of the line. From the graph, you can see that the y-intercept (the y-value from the point where the line crosses the y-axis) is 0. 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, -6) and (2, 6) so the slope becomes:

Plugging these values into the slope-intercept equation:

y = 3x + 0

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

b² - 10b + 21 = 0
(b - 3)(b - 7) = 0

For this expression to be true, the left side of the expression must equal zero. Therefore, either (b - 3) or (b - 7) must equal zero:

If (b - 3) = 0, b must equal 3
If (b - 7) = 0, b must equal 7

So the solution is that b = 3 or 7