Which is not true about a direct proportion? a. its graph must go through the origin. b. its graph must be linear. c. its graph must have a slope of 1. d. its graph must have a constant slope.

Answer is

C. Its graph must have a slope of 1.

Because the formula of direct proportion is

y=kx,

where is k is a number( constant), but it does not have to be equal 1.

were is the equation

3

step-by-step explanation:

in standard form:

a= dictionaries

b= maps

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

45+b=60

and then replace b with 15 to get the total:

45+15=60

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!