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3 years ago

Solve x2-14x+21=0 by completing the square

1 answer:

4 0

$x^2-14x+21=0\\\\x^2-2x\cdot7+7^2-7^2+21=0\\\\(x-7)^2-49+21=0\\\\(x-7)^2-28=0\\\\(x-7)^2=28\iff x-7=-\sqrt{28}\ \vee\ x-7=\sqrt{28}\\\\x=7-\sqrt{4\cdot7}\ \vee\ x=7+\sqrt{4\cdot7}\\\\x=7-2\sqrt7\ \vee\ x=7+2\sqrt7$

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Hey I need help just leave answer thx

Illusion [34]

Answer:

x = 61

Step-by-step explanation:

The angle above the line n adjacent to 2x - 6 is (x + 3) alternate angle.

Adjacent angles are supplementary, thus

2x - 6 + x + 3 = 180, that is

3x - 3 = 180 ( add 3 to both sides )

3x = 183 ( divide both sides by 3 )

x = 61

4 0

3 years ago

Consider the sequence: 3, 8, 13, 18, 23, ...The recursive formula for this sequence is:an = an-1 + 5In a COMPLETE sentence, expl

Leona [35]

Answer:

see the explanation

Step-by-step explanation:

we know that

In an Arithmetic Sequence the difference between one term and the next is a constant called the common difference

we have

$3, 8, 13, 18, 23,...$

Let

$a_1=3\\a_2=8\\a_3=13\\a_4=18\\a_5=23\\$

$a_2-a_1=8-3=5$ ------> $a_2=a_1+5$

$a_3-a_2=13-8=5$ ------> $a_3=a_2+5$

$a_4-a_3=18-13=5$ ------> $a_4=a_3+5$

$a_5-a_4=23-18=5$ ------> $a_5=a_4+5$

the common difference between consecutive terms is equal to 5

we can rewrite the formula as

$a_n=a_(_n_-_1_)+5$ -----> given formula

For n > 1

where

an is the term that you want to find (position n)

a(n-1) is the known term position (n-1)

Find a_8

For n=8

$a_8=a_(_8_-_1_)+5$

$a_8=a_7+5$

I need to know a_7

we know that

The general formula for arithmetic sequence is equal to

$a_n=a_1+d(n-1)$

where

an is the term that you want to find (position n)

a_1 is the first term

d is the common difference

n is the number of terms

we have

$a_1=3$

$d=5$

substitute

$a_n=3+5(n-1)$

$a_n=3+5n-5$

$a_n=5n-2$

For n=8

$a_8=5(8)-2$

$a_8=38$

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3 years ago

Which of these values would you most likely see on a U.S. speed limit sign?

Ira Lisetskai [31]

Answer:

A. 55 miles/hour

Step-by-step explanation:

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Ede4ka [16]

I would say the amount used would be at least 50 gallons because it makes most sense. Hope I helped :))

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3 years ago

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Question 13-14. Thanks

Mumz [18]

For number 14 she could fold the string in fours and for 13 it is 9

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4 years ago