Question 273581
the y intercept is the value of y when x = 0.


the x intercept is the value of x when y = 0


first equation is:


-x + 3y = 9


make x = 0 and this equation becomes 3y = 9 which makes y = 3


make y = 0 and this equation becomes -x = 9 which makes x = -9


the ordered pairs from this would be:


(0,3) for the y intercept.
(-9,0) for the x intercept.


to graph this equation, solve for y to get:


y = (1/3)*x + 3


graph looks like this:


{{{graph (600,600,-15,10,-5,15,(1/3)*x + 3)}}}


second equation is:


2x + 5y = -20 


y intercept is the value of y when x = 0


make x = 0 and the equation becomes 5y = -20


solve for y to get y = -4.


x intercept is the value of x when y = 0


make y = 0 and the equation becomes 2x = -20


solve for x to get x = -10


the ordered pairs from this would be:


(0,-4) equals the y intercept (value of y when x = 0)
(-10,0) equals the x intercept (value of x when y = 0)


to graph this equation, solve for y to get


y = (-2/5)*x - 4


graph of this equation looks like this:


{{{graph(600,600,-15,10,-15,5,(-2/5)*x - 4)}}}


you graph the equations manually by plotting the two points you created on graph paper and then drawing a straight line between them.