[tex]y = mx + b \\ m = slope /gradient \\b = y - intercept[/tex]
Substitute m = 1/3 in the equation.
[tex]y = \frac{1}{3} x + b[/tex]
[tex](x,y) = (0,2)[/tex]
[tex]2 = \frac{1}{3} (0) + b \\ 2 = 0 + b \\ 2 = b[/tex]
[tex]y = \frac{1}{3} x + 2[/tex]
[tex] \large \boxed{y = \frac{1}{3} x + 2}[/tex]
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