Answer:
B. Between 200 and 400
Step-by-step explanation:
Rule of exponents means that you can subtract when they are divided
-5+7=2
7.8*10^2/3.1
Simplify
780/3.1= 251.612903
1x 1 inch cube has volume 1in³, so 180 of these cubes can fit in a 180in³ space.
To complete the 100% of (the job) washing, Roland needed 4 Hours & Sam, 3 hour,
Mind you 100% = 1
Find for each one the (job) achieved in 1 hour:
Roland achieved 1/4 & Sam 1/3 each one in 1 hour.
In one hours both will achieve 1/4+1/3 =7/12
So they will complete 7/12 (of the job) in 1 hour & for a time = t they will complete 100% (or 1) of the job, that is 1/t =7/12 & t=12/7 =1.71 hour
To solve this algebraically, you can first factor out a 3:

Then, you can factor (I'm using guess and check) and my answer is -4 and 2:

From here on, finding 0s is very easy. You just solve for x in the parentheses. So,
the 0s are when x = 4, and x = -2. Remember, (4-4) = 0, and (-2+2) = 0, that's what you want.