At Dorothy's Hair Salon, 4 gallons of shampoo will last 3 weeks. She has 7 gallons of shampoo. How much more must she order if she wants to have enough for 12 weeks?

4x4=16-7=9gallons

She will order 9 gallons

Step-by-step explanation:

2 equivalent expressions to represent the area of a rectangle and the top is n-3 and the side is 2

area of the rectangle = length * width

given length = n - 3

width = 2

replace it in the area

so area of the rectangle = (n-3) *2

= 2(n-3)

one of the expression is 2(n-3)

to get another expression we distribute 2 inside the parenthesis

2(n-3) is 2n - 6

so another expression is 2n - 6

two equivalent expression are

2(n - 3)   , 2n - 6

we are given scale of 2 units.

on graph paper the space is 2.5 cm.

length of glass = 8 units.

8 units = 2 units +2 units +2 units +2 units.

each 2 unit is = 2.5cm.

therefore,

8 units = 2 units +2 units +2 units +2 units = 2.5+2.5+2.5+2.5= 10cm.