Question

Points $AandB$ have coordinates $(7,-3)and(1,9)$ respectively.

Find the value of $p$ if $(-2,p)$ lies on it.

Answer 1

Equation of AB :-

$y-9=\frac{9-(-3)}{1-7}(x-1)$

$\therefore y-9=-2(x-1)$

$\therefore y-9=-2x+2$

$\therefore 2x+9=11$

$\therefore$ If $(-2,P)$ lies on it

$\therefore -4+P=11$

$\therefore P=11+4=15$