Question

If the coordinates of A and B are (-3, a) and (1, a+4) respectively and the mid point of AB is (-1, 1),

then find the value of 'a'.​

Answer 1

`a=-1`

Using the midpoint formula directly from the topic meaning

`(x_(1)+x_(2) )/(2) or (y_(1)+y_(2) )/(2)`

so

`(a+a+4)/(2) =1\\a=-1`