The equation of a straight line with gradient m passing through the origin is:
[tex]\displaystyle y=mx[/tex]
The line passes through the origin, so the y-intercept is [tex]0[/tex]
[tex]\displaystyle y=mx+b[/tex]
[tex]\displaystyle y=mx+0[/tex]
[tex]\displaystyle y=mx[/tex]
