G3a
Practice - Slope of a Line
TRY TO ANSWER IN TWO AND A HALF MINUTES.
QUESTIONS
QUESTIONS
1. The equation for a line is ax + b = 0. The slope of the equation is positive. Then b is (greater than, equal to, or less than) zero.
2. What is the slope of a line parallel to 3y = 8x - 6?
3. What is the slope of a line perpendicular to the equation in Question 2?
4. Find the slope of the line that passes through the following pairs of points: (3,5) and (-1,2).
5. A line passes through the points (0,4) and (1,2). Which of these is the slope of the line? a) -4, b) -2, c) 2 or d) 4.
ANSWERS
1. b is greater than zero, because the slope is positive.
2. Parallel lines have the same slope. Put the equation into the slope-intercept form, which is y = (8/3) x -2. The slope is 8/3.
3. If the slope of the first line is 8/3, the slope of a line perpendicular to it is the negative reciprocal, or -(3/8).
4. The difference between the two x-values is 3 minus -1 = 4. The difference in the two y-values is 5 - 2 = 3. The ratio of the y-difference and the x-difference is 4/3.
5. The y-difference is 4 - 2 = 2. The x-difference is 0 - 1 = -1. The ratio of the differences is 2/-1 = -2. The correct answer is b).