Simple add them all 2+7+3+7+9 is 28 then divide 28 by the amount of numbers (5) to get 5.6 or if you are rounding to the nearest number 6... Hope this helped ;)
Remember PEMDAS - parentheses, exponents, multiply, divide, add, subtract
because multiply come before subtract, your first step would be 1/2 x 2 = 1
next, you subtract -> 15 - 1 = 14
14 is your answer
Answer:
x=3.4
y=-6.75
Step-by-step explanation:
5x+4y=-10 (equation 1 )
-5x+3y=-17 (equation 2)
7y=-27
y=-6.75
substitution (equation 1 ) y=-6.75
5x-27=-10
5x=17
x=3.4
Answer:
He answered 20 questions correctly.
Step-by-step explanation:
25×.8(80%) = 20.
Answer:
a. 
b. 
Step-by-step explanation:
First, we need tot find a general expression for the amount of caffeine remaining in the body after certain time. As the problem states that every hour x percent of caffeine leaves the body, we must substract that percentage from the initial quantity of caffeine, by each hour passing. That expression would be:

Then, to find the amount of caffeine metabolized per hour, we need to differentiate the previous equation. Following the differentiation rules we get:

The rate is negative as it represents the amount of caffeine leaving the body at certain time.