Answer:
change the expression to y
Step-by-step explanation:
[tex]x + 3y = 9[/tex]
[tex]3y = - x + 9[/tex]
[tex]y = \frac{ - 1}{3} x + \frac{9}{3} [/tex]
the gradient is the coefficient of x,
[tex] - \frac{1}{3} [/tex]