Question

Line through the points (-2,6) and (4,8) is perpendicular to the line through the points (8,12) and (x,24). Find the value of x.

• A. -4
• B. 4
• C. 3
• D. -3

Answer 1

Answer:

B. 4

Slope of the line passing through the points (-2,6) and (4,8)

$m_1=\frac{8-6}{4+2}=\frac{2}{6}=\frac{1}{3}$

Slope of the line passing through the points (8,12) and (x,24)

$m_2=\frac{24-12}{x-8}=\frac{12}{x-8}$

$m_1 \times m_2=-1$

$\frac{1}{3}\times\frac{12}{x-8}=-1$

$12=-3x+24$

$3x=12$

$x=4$