Straight line graphs

• The gradient is the steepness or slope of a straight line.
• A negative gradient indicates that as one variable decreases, so does another.
• m = gradient
• Gradient = change in y / change in x
• If two variables are directly proportional to each other, their product remains constant.
• If two variables are directly proportional to each other, their product remains constant.
• 2 lines are perpendicular

  The product of their gradient is -1 and they are negative reciprocals