A horizontal line goes straight across, and its equation is , where b is the y-value of every point on it. A vertical line goes straight up and down, and its equation is . Horizontal lines have a slope of 0. Vertical lines have an undefined slope. Before this lesson: You should know how to…
Slope tells you how steep a line is and which way it goes. It is the rise (how far the line goes up or down) divided by the run (how far it goes across). To find slope from two points, use the slope formula: . Before this lesson: You should know how to plot points…
The x and y intercepts are the points where a graph crosses the axes. To find the x-intercept, set y = 0 and solve for x. To find the y-intercept, set x = 0 and solve for y. For 3x + 2y = 12, the intercepts are (4, 0) and (0, 6).
A two-variable linear equation, like 2x + y = 5, has two variables and makes a straight line when you graph it. Its solutions are ordered pairs (x, y) that make the equation true, such as (1, 3). To graph it, find a few solutions, plot them, and draw a line through them.
Multi-step inequalities are solved like multi-step equations: distribute, combine like terms, and get the variable terms on one side. Then undo adding or subtracting, and multiplying or dividing. Flip the sign only if you multiply or divide by a negative number. For example, gives , so . Before this lesson: You should know how to…
Two-step inequalities, like , are solved like two-step equations: undo adding or subtracting first, then undo multiplying or dividing. If you multiply or divide by a negative number, flip the inequality sign. Here, , so . Then graph the answer on a number line. Before this lesson: You should know how to solve one-step inequalities…
A one-step inequality, like , is solved like a one-step equation: do the inverse operation to both sides. There is one new rule for one-step inequalities. If you multiply or divide both sides by a negative number, flip the inequality sign. The answer, , is a range of numbers you can graph on a number…
Multi-step equations take more than two steps to solve. First simplify each side: use the distributive property to remove parentheses, then combine like terms. Then solve the two-step equation that is left. For example, simplifies to , so . Before this lesson: You should know how to solve two-step equations, use the distributive property and…
A two-step equation needs two inverse operations to solve, like . To solve two-step equations, first undo the adding or subtracting, then undo the multiplying or dividing. Do each step to both sides: becomes , so . Before this lesson: You should know how to solve one-step equations and how to use the order of…
A one-step equation takes just one operation to solve. To solve one-step equations, undo the operation on the variable with its inverse: subtract to undo adding, add to undo subtracting, divide to undo multiplying, and multiply to undo dividing. Do the same thing to both sides. For example, gives . Before this lesson: You should…