Answer:
(4, -3)
Step-by-step explanation:
To solve this with graphing all you need to do is enter both equations in a graphing calculator (you can use desmos online) and then find the point where both lines intersect.
Yes, all your answers are correct.
They are correctly matched with their reasons.
-4
y=-4x-9
y=mx+b
m=slope
Ellie can make eight stacks of quarters with four quarters in each stack