(6, -7) = (x, y)
In polar coordinates we will have (x , y) = ( r , θ)
r = sqrt ( x^2 + y^2) θ = arctan (y /x) ....this is in rads
r = sqrt ( 6^2 + (-7)^2 ) = sqrt (36 + 49) = sqrt ( 85)
θ = arctan (y /x) = arctan ( -7/6) ≈ -0.862
So (6, -7) = ( sqrt (85), -0.862 ) in polar form
See if you can do the second one....