1) Substitution from definition.
2) We use 
3) We are changing the order of 3 and 
.
4) We add 1 and 3 and we get 
5) Substitution from definition (but the other way than at the beginning).
The answer would be A= 3 because, 3x3= 9 then you add 9+1 and get 10
Hope this helps
72, 80, and 90 are all numbers that fit the rule
Answer:
'Twice the sum of a number and 5' can be translated into variable expression such as:
Step-by-step explanation:
Given the phrase
<em>Twice the sum of a number and 5</em>
First, let us breakdown the English Phrase
Let the number be = n
The sum of a number 'n' and 5 = n + 5
now, twice the sum of a number and 5 can be determined by multiplying (n+5) with 5.
Thus,
'<em>Twice the sum of a number and 5</em>' can be translated into variable expression such as:
speed = distance/time
distance = speed * time
d = st
time up the mountain: t
time down the mountain: 6.6 - t
distance each way: d
Up the mountain:
d = st
d = 80t
Down the mountain
d = st
d = 85(6.6 - t)
The distances are equal, so
80t = 85(6.6 - t)
80t = 561 - 85t
165t = 561
t = 3.4
6.6 - t = 6.6 - 3.4 = 3.2
It takes 3.4 hours up the mountain and 3.2 hours down the mountain.
3.4 hours at 85 mph covers the same distance as 3.2 hours at 85 mph.
3.4 hours * 80 mph = 272 miles
3.2 hours * 85 mph = 272 miles
