Answer:
80
Step-by-step explanation:
every triangle adds up to 180 sort of, in this case, turn 4 into 40. 40+20=60 so add 80 to be 180!!!
This is a combination problem. Order does not matter and the books are all different. You would write this as 21C5 or
. Combinations are not fractions.
The answer is 
which = 20349 different ways these books can be chosen.
So that equation was definitely correct...
When you expand the equation in the bracket you'll find out that you'll get a^6 + 4a^4 + !6a^2 - 4a^4 - 16a^2 -64. then your final result will be a^6 - 64
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Answer:
180
Step-by-step explanation:
180 because it is obtuse
Answer:
Step-by-step explanation:
Let
be the greater number and
be the smaller number. We know that their difference is 15, so we have

Then, we have the following information: if we add twice the greater (2x) and 8 (2x+8), the result is 3 times the lesser (3y) minus four (3y-4). So, we have

So, we have the follwing system:

From the first equation, we can derive
, and substitute this expression in the second equation to get

Substitute this value for y in the first equation to get
