*Straight line      Function y = m x + c represents a straight line cutting + y at acute angle to +x.

*Straight line     

Function y = m x + c represents a straight line cutting + y at acute angle to +x.

m = tanq is called slope of the line.

q = anticlockwise angle made by the line with + x axis.

m = +ve if line makes acute angle to +x.

m = 0 if line is horizontal.

m = – ve if line makes obtuse angle to +x.

c = +ve if line cuts +y.

c = – ve if line cuts -y.

c = 0 if line passes through origin.