well, the total cost must be less than or equal to 77
total cost=tangfishcost+clownfishcost
tangfishcost=costpertangfish times numberoftangfishboubht=15 times x
clownfishcost=costperclownfish times numberofclownfishbought =11 times y
15x+11y≤77 is the equation
graph the line 15x+11y=77
in slope intercept form
y=-15/11x+7
graph points (0,7) and (11,-8)
connect them with a solid line
first make a boundary, x and y cannot be negative because they are counting how many you can buy
so restrict the graph to y≥0 and x≥0
anything where y<0 or x<0, erase that line
now
test 1 point to see if it is in the solution set
15x+11y≤77
test (0,0)
0≤77
true
shade whre that is (to bottom left)
graph below
a solution that is not acceptable is (-3,0) because you can't buy -3 fish
another one is (100,30) because you don't have enough money
