Priamka - spád a úsek vyťatý na súradnicovej osi y
Author: D.Velichová

m = 1.200000000000001 (slider from -10 to 10, step 0.1)
c = -2 (slider from -5 to 5, step 0.1)
a: y = m x + c
A: (0, c)
text1: "y =  " + m + "x  " + c