To turn something into the slope-intercept form
⇒ must know the slope-intercept form ⇒ [tex]y = mx +b[/tex]
To convert our current form into slope-intercept form
⇒ must solve for 'y'
⇒ (in other words) move everything to one side and 'y' by itself on the
other
[tex]3y - 9x = -81\\3y =9x-81\\y = 3x - 27[/tex]
*purely extra information (not necessary for final answer)
Slope-intercept form: y = 3x - 27
Hope that helps!