sat suite question viewer
| xx | yy |
|---|---|
| -6−6 | 6565 |
| -3−3 | 5656 |
| 33 | 3838 |
| 66 | 2929 |
The table shows four values of x and their corresponding values of y. There is a linear relationship between x and y. Which of the following equations represents this relationship?
Explanation
Choice A is correct. An equation representing the linear relationship between x and y can be written in slope-intercept form y=mx+b, where m is the slope of the graph of the equation in the xy-plane and (0,b) is the y-intercept. The slope, m, can be calculated using two ordered pairs, (x1,y1) and (x2,y2), and the formula m=y2−y1x2−x1. Substituting the ordered pairs (−6,65) and (6,29) from the table for (x1,y1) and , respectively, in this formula yields , which is equivalent to , or . Substituting for in the formula yields . Substituting the point into this equation yields , or . Subtracting from both sides of this equation yields . Substituting for in the equation yields . Adding to both sides of this equation yields . Multiplying both sides of this equation by yields .
Choice B is incorrect. Substituting the point from the table into this equation yields , or , which is false.
Choice C is incorrect. Substituting the point from the table into this equation yields , or , which is false.
Choice D is incorrect. Substituting the point from the table into this equation yields , or , which is false.