7(2x + 5) - 3(x - 4)
14x + 35 - 3x + 12
11x + 47 <==
First convert all of the fractions into the same denominator. 1/3 = 2/6. Add the new fraction of history books and the fraction for english books. 2/6 + 1/6 = 3/6. Subtract the total from 1 or 6/6. 6/6 - 3/6 = 3/6. The answer is 3/6 or 1/2 when reduced. 50% or 1/2 of the books are science books.
From what I see in the problem, the expression is
To solve, plug in a and k.
3*5^2=75
(3*5)^-1 = 1/15
5^-2 = 1/25
400m = .4 km
so in a day she runs 4000m = 4km
3*4000 = 12000
12000/400 = 30 laps is your answer
750ml= 0.75l
250ml=0.25l
2L+(0.75L+0.25L)+1.5L= 4.5L
One L left, to find original amount
4.5L+1L=5.5L