The slope of line k is (0 - 9)/(-1 - 2) = -9/-3 = 3. Since (n, 21) is also on the line, the slope between this point and any other point on line k, say (-1, 0), should be 3 also. So we have:AAPL wrote:Magoosh
In the \(xy-\)coordinate system, points \((2, 9)\) and \((-1, 0)\) lie on line \(k\). If the point \((n, 21)\) lies on line \(k\), what is the value of \(n\)?
A. 6
B. 7
C. 8
D. 9
E. 10
OA A
(21 - 0)/(n - (-1)) = 3
21/(n + 1) = 3
7 = n + 1
6 = n
Answer: A
