Alberto and 9 of his friends went out to eat.
1 + 9 = 10
So there are 10 people in total.
Each person paid the same amount, $18.
18 × 10 = 180
The total bill was $180.
C (third graph, the parabola); To find if it is a function or not draw a vertical line on the graph. If the vertical line could never intercept the figure more than once anywhere on the graph then it is a function.
What?
The slope can be found between two points by finding the change in values divided by the change in values.