Storing Math.Numerics.Fit.Line data into two separate variables simultaneously

Question

I am working on a excercise here which is gathering data from a file and then displaying it on graph.

I am using a linkedIn video to help me here but I stumped on how they are able to store this extension method into two separate variables at the same time.

var (intersect,slope) = MathNet.Numerics.Fit.Line(arrx.ToArray(), arry.ToArray());

If I keep one variable on the left side the red lines go away but if I keep both "intersect" and "slope", it gives me an error.