Key Concepts

• An ordered pair [latex](x,y)[/latex] tells the location of a point relative to the point’s location along the horizontal x-axis and along the vertical y-axis.
• To graph a linear equation, create a table of values for x and y, and then plot these ordered pairs on the coordinate plane. Then draw a line through the points.
• The slope-intercept form for the equation of a line is [latex]y=mx+b[/latex] where m and b are real numbers, m = slope and b = y-intercept.

• The slope of a line, m, represents the change in y over the change in x. Given two points, [latex](x_1, y_1)[/latex] and [latex](x_2, y2)[/latex], the slope of the line is [latex]m=\frac{y_2-y_1}{x_2-x_1}[/latex]. If x increases by 1 unit, y changes by m units.
• The y-intercept, b, is the point where the line crosses the y-axis. The y-intercept tells us the value of y when x = 0.

Glossary

• Origin: the point where the horizontal and vertical axes intersect at 0 on the x-axis and 0 on the y-axis
• Quadrants: the four sections of the coordinate plane formed by the intersection of the x– and y-axes
• Linear relationship: a relationship between variables such that when plotted on a coordinate plane, the points lie on a line