A stockbroker dealt with 30 customers on a certain day. Of these, 12 bought and sold stocks and 17 sold stocks (but did not buy). How many of the customers bought stocks (but did not sell)?

25

Step-by-step explanation:

30=17+x-12

the slope of the line is 60

one point on the line is (40,10)

step-by-step explanation:

in the equation outside the parenthesis the equation always tells you the slope. in this case it is 60.

in the parenthesis is also says 40 which is x because it is near the x and 10 is y because it is near y.