In 6th grade lilly read 15 books. this year in 7th grade she rad 18 books. what is the percent of increase in the number books that lilly read this year?

20%

Step-by-step explanation:

To solve this problem you must apply the proccedure shown below:

1. You must apply the following formula (Let's call the percent of increase:):

2. Substitute values and solve:

%

x =-.20752

step-by-step explanation:

4^(x+2)=12

4^(x+2)=12

take the log base 4 on each side

log 4 (4^(x+2) = log 4(12)

we know log b(a^y) = y log b (a)

(x+2) log 4(4) = log 4 (12)

x+2 = log 4 (12)

we know   logb c = loga c/loga b

we want to convert to base 10   so a = 10

by default, we do not write the 10   c = 4   and b = 10

log4 10 = log 12/log 4

log4 10 = log 12/ log 4

x+2 = log 12/ log 4

subtract 2 from each side

x +2 -2 = log 12/ log 4 -2

x = 1.79248125 -2

x =-.20752

f(x)=4

step-by-step explanation: