Question

If the points $(1,0),(0,1)$ and $(x,8)$ are collinear, then the value of $x$ is equal to

• A. 5
• B. -6
• C. 6
• D. 7
• E. -7

Answer 1

Answer: (E)

Let $A(1,0),B(0,1)$ and $C(x,8)$
Since, $A,B$ and $C$ are collinear, then slope of $AB=$ Slope of $BC$
$\Rightarrow \frac{1-0}{0-1}=\frac{8-1}{x-0}$
$\Rightarrow -1=\frac{7}{x}$
$\Rightarrow x=-7$