Question

find all points having a y-coordinate of -3 whose distance from the point (1,2) is 13

Answer 1

Distance formula for distance between two points \((x_1,y_1),(x_2,y_2)\) is \[d = \sqrt{(x_2-x_1)^2+(y_2-y_1)^2}\]

You know \((x_1,y_1)=(1,2)\) and \(y_2 = -3\) and \(d = 13\)

Plug everything in and solve for \(x_2\)

Answer 2

don't forget to take both positive and negative values of the square root!

Answer 3

thanks , i know this but my last step is x^2-2x-143 , i can't factorise it cause of 143

Answer 4

Complete the square, or use the quadratic formula?

Answer 5

Or remember that 143 = 11*13

Answer 6

oh okay thanks so much , i go try it now =)