There has to be more to this question then i can help you
21.
So to solve for the value of a variable in an equation, you would need to isolate x on one side. The first thing you have to do is multiply 2 and (x + 7) together, which can be rewritten as 2(x) + 2(7). After multiplying, your equation would be:
, or A.
22.
So the rule with multiplying exponents with the same base is to add the exponents together, and the rule with dividing exponents with the same base is to subtract the exponents. Your equation will be simplified as such:

Now the rule with converting negative exponents into fractions is
. In this case, 4^-2 would turn into
, or C, which is your final answer.
To answer the question above, I let x be the number of calendars sold. You may use any other letter as this is just for representation. The total income generated in selling calendars is calculated by multiplying the number of calendars with the price. That is,
total income = 5x
If we let total income be y, our equation is further simplified into,
y = 5x
Answer:
4 hours
Step-by-step explanation:
First we need to subtract the one pay fee (the helmet rental fee, $15)
So 51 - 15 = 36
Then we need to divide 36 by the amount of money it costs for each hours to find how many hours he rented the bike
So 39/9 = 4