Question

The points (-2,-5), (2, -2) and ( 8,a) are collinear , then the value of a is
(a) -2.5 (b) 2.5 (c) 1.5 (d) 0.5 (e) none of these

Answer 1

Answer:

a = 2.5

Step-by-step explanation:

( $x_{1}$ , $y_{1}$ )

( $x_{2}$ , $y_{2}$ )

Slope of the line passing through those two points

m = $\frac{y_{2} -y_{1} }{x_{2} -x_{1} }$

~~~~~~~~~~~~~~

( - 2 , - 5 )

( 2 , - 2 )

( 8 , a )

m = $\frac{-5+2}{-2-2}$ = $\frac{3}{4}$

$\frac{-2-a}{2-8}$ = $\frac{3}{4}$

- 2 - a = - 4.5

a = 2.5