A line segment is bisected by a line with the equation 4 y + x = 8 . If one end of the line segment is at (5 ,2 ), where is the other end?

1 Answer
Jan 3, 2017

B = (75/17, -6/17), AB ⊥ r, |AM| = |MB|

Explanation:

A = (5, 2)

r: y = 2 - 1/4 x

s ⊥ r Rightarrow s : y = a + 4x

A in s Rightarrow 2 = a + 4 * 5 Rightarrow a = -18

s cap r = M: 2 - 1/4 x = -18 + 4x // this is cohordinate x of M

8 - x = -72 + 16x Rightarrow 80 = 17x

M = (80/17, 2 - 20/17) = (A + B)/2 // middle point of A and B

80/17 = (5 + x)/2 and 14/17 = (2 + y)/2 // cohordinates of B

160 = 85 + 17x and 28 = 34 + 17y

75 = 17x and -6 = 17y