I NEED HELP WITH PRECALC PLEASE

First question: D, Second question: A

Step-by-step explanation:

Note: I'm not so good at expanding so I'll just solve it :)

So this leaves either C or D

Apply the sum rule:

8-70=-62

The only one that gives a negative sum is D

For the second picture, the one you have chosen is correct

a1 = 3 and r = -5 so:

an = 3/5 * (-5)^n

Plugging in 8 for n (the first choice) we get the given term: -234,375

Step-by-step explanation:

Putting n = 0 and n = 1 into the expression being summed will show you which series is correct.

  2 -7n for n=0 is 2 -7·0 = 2

  2 -7n for n=1 is 2 -7·1 = -5

The series of the last choice (d) is correct.

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The given sequence is exponential with a first term of 3 and a common ratio if -5. Then the n-th term is ...

  an = 3(-5)^(n -1)

We want to find n for an = -234,375.

  -234375 = 3(-5)^(n-1)

  -78125 = (-5)^(n-1)

For n to be a real number, we must have n even. In that case, the value of n is equivalent to the value that is the solution to ...

  78125 = 5^(n -1)

Taking logs of both sides, we get ...

  log(78125) = (n -1)·log(5)

  log(78125)/log(5) = n -1 . . . . . . . . . . . . divide by log(5)

  n = 1 +log(78125)/log(5) = 1 +7 = 8 . . . add 1 and evaluate

-234,375 is the 8th term of the sequence.

the answer is b.

step-by-step explanation:

identity property is where 0+whatever number=whatever number. basically 0+ a number.

d. $180

step-by-step explanation:

if the dimensions of the room is 9ft by 12 ft, we have the area of the floor as,

so the area of the floor is 108 square feet, converting that into square yards we get,

the cost of carpet is $15 per square yard, therefore the cost of carpet for 12 square yards is,

hence, the cost of carpet is $180.

assuming the dimensions of the room be,

15 ft by 12 ft

so, the area of the floor of that room is,

we can convert 180 square feet into square yards, we know that,

1 sq ft = 0.111 sq yard

so, 180 square feet is,

so the area of floor is 20 square yards.

now, the cost of carpet is 15 dollars per square yard, therefore the cost of carpet for 20 square yards is,

so, it will cost $300.