The question is
Find out the linear equation between the cost in dollar and the number of donuts holes
x -----> the number of donuts holes
y ----> the cost in dollars
we have the ordered pairs
(20,4) and (40,7)
Find the slope m
The formula to calculate the slope between two points is equal to
substitute the values
Find the equation of the line in point slope form
Find the equation of the line in slope intercept form
Isolate the variable y
1. is 4 and 2. is 3
so if you look at the first one you see that 1 is to 4 and 2 is to 8 and so on, so you can see for every 1 there is a times 4 so if it were 3 then it would be 3*4 and it is 12
for number 2 it is 3 because 1 is to 3 and 2 is to 6 so for every 1 there is 3 so if it were 3 then there would be 3*3 = 9
in standard form:
you have to buy 3 dictionaries, so put a 3 next to the a (dictionaries) so that you can multiply them by each other.
a3+b= 60 (the amount of money you have)
we already know the cost of a=15 so replace a with $15
($15 x 3)+b=60
multiply 15 and 3 to get $45 and replace it with $45
and then replace b with 15 to get the total:
that means you have $15 left after buying 3 dictionaries.
15 divided by the cost of a map ($5) equals 3.
so you can buy 3 maps.
sorry if it was confusing!