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3 years ago

Evaluate 2x2 - 1 when x = 3.

Mathematics

2 answers:

myrzilka [38]3 years ago

7 0

When x is evaluated to 3 you get 11.

2(3)2-1 = 11

tigry1 [53]3 years ago

6 0

X should equal 11
2(3)2-1
6(2)-1
12-1
11

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Find the value of 1.5l²m×2.4lmn² if l = 1,m = 0.2 and n= 0.5

Paraphin [41]

Answer:

plug in the numbers and multiply

Step-by-step explanation:

then do the exponents I hope this hleps

6 0

3 years ago

What is the first step in solving this quadratic equation? x^2+5x=6

evablogger [386]

Answer:

c) subtract 6 from both sides to get it equal to 0

Step-by-step explanation:

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4 years ago

Determine formula of the nth term 2, 6, 12 20 30,42

nalin [4]

Check the forward differences of the sequence.

If $\{a_n\} = \{2,6,12,20,30,42,\ldots\}$ , then let $\{b_n\}$ be the sequence of first-order differences of $\{a_n\}$ . That is, for n ≥ 1,

$b_n = a_{n+1} - a_n$

so that $\{b_n\} = \{4, 6, 8, 10, 12, \ldots\}$ .

Let $\{c_n\}$ be the sequence of differences of $\{b_n\}$ ,

$c_n = b_{n+1} - b_n$

and we see that this is a constant sequence, $\{c_n\} = \{2, 2, 2, 2, \ldots\}$ . In other words, $\{b_n\}$ is an arithmetic sequence with common difference between terms of 2. That is,

$2 = b_{n+1} - b_n \implies b_{n+1} = b_n + 2$

and we can solve for $b_n$ in terms of $b_1=4$ :

$b_{n+1} = b_n + 2$

$b_{n+1} = (b_{n-1}+2) + 2 = b_{n-1} + 2\times2$

$b_{n+1} = (b_{n-2}+2) + 2\times2 = b_{n-2} + 3\times2$

and so on down to

$b_{n+1} = b_1 + 2n \implies b_{n+1} = 2n + 4 \implies b_n = 2(n-1)+4 = 2(n + 1)$

We solve for $a_n$ in the same way.

$2(n+1) = a_{n+1} - a_n \implies a_{n+1} = a_n + 2(n + 1)$

Then

$a_{n+1} = (a_{n-1} + 2n) + 2(n+1) \\ ~~~~~~~= a_{n-1} + 2 ((n+1) + n)$

$a_{n+1} = (a_{n-2} + 2(n-1)) + 2((n+1)+n) \\ ~~~~~~~ = a_{n-2} + 2 ((n+1) + n + (n-1))$

$a_{n+1} = (a_{n-3} + 2(n-2)) + 2((n+1)+n+(n-1)) \\ ~~~~~~~= a_{n-3} + 2 ((n+1) + n + (n-1) + (n-2))$

and so on down to

$a_{n+1} = a_1 + 2 \displaystyle \sum_{k=2}^{n+1} k = 2 + 2 \times \frac{n(n+3)}2$

$\implies a_{n+1} = n^2 + 3n + 2 \implies \boxed{a_n = n^2 + n}$

6 0

2 years ago

Solve this equation for X. If necessary, round your answer to the nearest integer<img src="https://tex.z-dn.net/?f=%282x%20%2B%2

Hatshy [7]

Answer

x = 1

Explanation:

Given the following equation

$\begin{gathered} (2x+2)^{\frac{1}{2}}=\text{ -2} \\ \text{According to the law of indicies} \\ x^{\frac{1}{2}}\text{ = }\sqrt[]{x} \\ (2x+2)^{\frac{1}{2}}\text{ = }\sqrt[]{(2x\text{ + 2)}} \\ \text{Step 1: Take the square of both sides} \\ \sqrt[]{(2x\text{ + 2) }}\text{ = -2} \\ \sqrt[]{(2x+2)^2}=-2^2 \\ 2x\text{ + 2 = 4} \\ \text{Collect the like terms} \\ 2x\text{ = 4 - 2} \\ 2x\text{ = 2} \\ \text{Divide both sides by 2} \\ \frac{2x}{2}\text{ = }\frac{2}{2} \\ x\text{ = 1} \end{gathered}$

Therefore, x = 1

5 0

1 year ago

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Which statement is true about the circumference of a circle?

MAVERICK [17]

The circumference is the measurement around the circle.

6 0

4 years ago

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