Afood truck sells salads for $6.50 each drink for $2.00 each. the food trucks revenue fron selling a total of 209 salads and drinks in one day was $836.50. if the truck sold a total of. 116 drinks how much salads were sold that day?

S = # of salads
d = # of drinks

$6.5s + $2d = $836.5
s + d =209

1. Isolate a variable.

s = 209-d

2. Plug in.

6.5 (209-d) + 2d = 836.5

1358.5 - 6.5d + 2d = 836.5
-4.5d = -522
d = 116

s = 209 - 116 = 93

First locate the turning point (vertex) of the graph. which is at the coordinates x=5 and y=9 or (5; 9).to determine whether it's a maximum or mininum value, you have to discern whether the vertex's y-value is the highest value or lowest value the graph can reach. since the vertex's y-value, 9 is the highest value the graph can reach, it will be a maximum.another basic way to determine whether the vertex's value is max or min is to see if the graph is smiling or sad. if it's smiling, the turning point/vertex would be a minimum, while a sad parabola would have a maximum y-value at the vertex.