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3 years ago

Mathematics sat question

Mathematics

2 answers:

Tanzania [10]3 years ago

6 0

Answer:

A) a^2 + a

Step-by-step explanation:

So the problem says "sum" which means you have to add the expressions

(a^2) - 1 and a+1

Work:

((a^2) - 1) + (a + 1)

We can simplify only the constants

(a^2) + a + 1 - 1

(a^2) + a

so the answer is A

navik [9.2K]3 years ago

5 0

Answer: A) $a^{2}$ + a

add the two equations together to get A.

the ones cancel eachother out and you cant add $a^{2}$ to a

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I need help ill give brainiest

Gnoma [55]

Answer:

9 ft

Step-by-step explanation:

its volume is equal to the area by height;

(2.5 x 3)h = 67.5

h = 9ft

5 0

3 years ago

Read 2 more answers

Select each pair of functions that are inverses of each other

svlad2 [7]

Answer:

The first two choices only: A and B.

Step-by-step explanation:

The inverses are the ones with one relation having point (x,y) and the other relation having point (y,x). This most obvious when looking at points on a table or a list of points.

So the first pair are inverses because per point (x,y) on the first list you have (y,x) on the second list.

Examples:

1st list contains (-5,-9) while second list contains (-9,-5).

1st list contains (3,7) while the second list contains (7,3).

As long as (a,b) is in the first list and (b,a) is in the second or vice versa, then the pair of relations are inverses. So the first choice contains inverses.

Now lets talk about the pair of functions given in function notation.

Let's start with the first.

y=x+7

Extend the first idea more. Just swap x and y and then see after solving for y if what it equals is what g equals then f and g are inverses in the second choice.

x=y+7

Subtract 7 on both sides:

x-7=y

y=x-7

This is what g equals so the second choice is an answer.

The last choice does not contain a pair of inverses. Example: (2,3) is in the first list but (3,2) is not in the second.

6 0

3 years ago

Read 2 more answers

How do i calculate? All the way to s_75. It’s so long

mina [271]

Answer:

-675

Step-by-step explanation:

The sum can be broken into parts that you know. Here, one of those parts is the sum of numbers 1 to n. That sum is given by n(n+1)/2.

$\displaystyle S_{75}=\sum\limits_{n=1}^{75}{(67-2n)}=\sum\limits_{n=1}^{75}{67}-2\sum\limits_{n=1}^{75}{n}\\\\=75\cdot 67-2\dfrac{75(75+1)}{2}=75(67-76)\\\\=\bf{-675}$

Another way to do this is to realize the sequence of numbers is an arithmetic sequence with a first term of 65 and a last term of 67-2·75 = -83.

The sum of an arithmetic sequence is found by multiplying the number of terms by their average value. Their average value is the average of the first and last terms.

The average value of those 75 terms is (65 +(-83))/2 = -9, so their sum is ...

75(-9) = -675

7 0

3 years ago

Is –22 + 9 positive or negative?

12345 [234]

Negative since the answer would be -13

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3 years ago

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Simplify: 9(1 - r) + 3r

Butoxors [25]