Question

Point B has coordinates ​(2​,1​). The​ x-coordinate of point A is -10. The distance between point A and point B is 15 units. What are the possible coordinates of point​ A?

Answer 1

(-10, 10) or (-10, -10)

Explanation:

`d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2`

`15 = √((-10 - 1)^2 + (y_2 -2 )^2)`

`15 = √(121 + 2y + y^2 + 4)`

`(15)^(2) =( √(121 + 2y + y^2 + 4))^(2)`

`225 = 121 + 2y + y^2 + 4`

`225 = 125 + 2y + y^2`

`0 = -100 + 2y + y^2`

`0 = (y + 10)(y - 10)`