Answer 1

We have three collinear points A (x , 2 ) ; B ( -3 ,-4) ; C(7 , - 5).

In general if A (x₁ , y₁) ; B (x₂ , y₂) ; C (x₃ , y ₃). are collinear then,

`x_1 ( y_2 -y_3) + x_2 (y_3 - y_1) + x_3 (y_1 - y_2 ) = 0`

So,

x (-4 + 5 ) -3 (-5-2)+ 7 (2 +4) = 0 

So,

`x + 42 + 21 = 0`

Therefore,

x = - 63