Answer:
f(n) = -n^2 -3n +5
Step-by-step explanation:
Suppose the formula is ...
f(n) = an^2 +bn +c
Then we have ...
f(1) = 1 = a(1^2) +b(1) +c
f(2) = -5 = a(2^2) +b(2) +c
f(3) = -13 = a(3^2) +b(3) +c
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Here's a way to solve these equations.
Subtract the first equation from the second:
-6 = 3a +b . . . . . 4th equation
Subtract the second equation from the third:
-8 = 5a +b . . . . . 5th equation
Subtract the fourth equation from the fifth:
-2 = 2a
a = -1
Then substituting into the 4th equation to find b, we have ...
-6 = 3(-1) +b
-3 = b
and ...
1 = -1 +(-3) +c . . . . . substituting "a" and "b" into the first equation
5 = c
The formula is ...
f(n) = -n^2 -3n +5
Answer:
2. B
3. B
4. 2(7k+5h)
5. $325
Step-by-step explanation:
2) "X decreased by the sum of 2x + 5" Decreased means to be lowered, so that means this problem has subtraction in it. It also says x is being decreased BY the sum of 2x + 5 so that means 2x + 5 needs to be solved, which calls for parentheses. B best fits the description.
3) It is B because if you distribute the 8 to 2a and 3b, you'll get 16a and 24b, which is the given expression.
4) The given expression is 10h + 14k and in the equivalent expression, you are given 5h. To get from 10 to 5, you must divide by 2. This tells you that 2 is being distributed, so you put 2 before the parentheses. Since you divided 10 by 2, you want to do the same to 14, which is 7. Therefore, it is 2(7k+5h).
5) You are given the hourly charge, which is $25. This means that they charge $25 per hour/for every hour. You want to find the cost for 13 hours, so you multiply the hourly charge by 13 hours. 25 x 13 = 325.
yes it should be the answer
Answer:
60 square units
Step-by-step explanation:
