Tham khảo tài liệu 'new sat math workbook episode 2 part 7', ngoại ngữ, ngữ pháp tiếng anh phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Additional Geometry Topics Data Analysis and Probability 285 Solution The correct answer is A . For each line formulate its equation by determining slope m theny-intercept b . For the pairs 0 2 and 2 0 y 2-0 x b slope -1 0 -2 b 2 b The equation for the line is y -x 2. For the pairs -2 -1 and 2 1 1 1 1 y 2 2 x b slope 2 1 1 2 b 0 b The equation for the line is y -2 x. To find the point of intersection solve for x and y by substitution. For example 2 x x 2 2 x 2 x 4 y 3 The point of intersection is defined by the coordinate pair 4 j . Example Referring to the xy-plane above if the scales on both axes are the same which of the following could be the equation of line P A y 5 x - 2 B y -2 x 2 C y 2 x - 2 D y 5 x 5 E y -2 x - 2 Solution The correct answer is E . Notice that line P slopes downward from left to right at an angle greater than 45 . Thus the line s slope m in the equationy mx b -1. Also notice that line P crosses the y-axis at a negative y-value that is below the x-axis . That is the line s y-intercept b in the equation y mx b is negative. Only choice E provides an equation that meets both conditions. 286 Chapter 16 Exercise 3 Work out each problem. Circle the letter that appears before your answer. 1. In the xy-plane what is the slope of the line described by the equation 2y -9 A -2 B -9 C 0 D 2 E The slope is undefined. 2. In the xy-plane what is the slope of a line that contains the points -1 4 and 3 -6 A - 2 C -2 B -2 D 1 E 2 3. In the xy-plane what is the equation of the line with slope 3 if the line contains the point defined by the xy-coordinate pair -3 3 A y 3x - 3 B y 3x 12 C y x 6 D y -3x - 12 E y 6x - 6 4. Referring to the xy-plane below if the scales on both axes are the same which of the following could be the equation of line P A y 3x - 6 B y 3 x - 6 C y -2 x 6 D y 3 x 6 E y -2 x - 6 5. What is the equation of the line that is the perpendicular bisector of the line segment connecting points 4 -2 and -3 5 in the xy-plane A y -x
