Easy
lets say
(x)(x+3)(x+1)
multiply out
x^3+4x^2+3x
ok so factor out x firs
x(x^2+4x+3)
factour inside
x(x+3)(x+1)
The answer should be 32 2/3. Sorry I'm late, but hope this helps.
Answer:

Step-by-step explanation:
Factor out a 6 from the numerator and 2 from the denominator
2 in the denominator divides the 6 in the numerator
factor the denominator, let me know if you need help with this
the (x+6)s cancel
1/5=20%
4 gallons. 100%
x gallons. 20%
x=4•20/100
x=80/100
x=8/10
x=4/5
Mrs. Zirkle will use 4/5 gallons of milk.
I am not 100% sure.