Help! Can some one explain Jessica has her hair styled and wants to tip her hair stylist 18%. Write an equation that could be used to calculate the tip, y, for a bill of x dollars.

y = .18x

Step-by-step explanation:

The tip is going to be 18% of what she payed, and this says that x is what she payed. That means you can write it as:

tip = 18% of bill

y = 18% of x

18% of x an be written as .18x in decimal, so:

y = .18x

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional