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3 years ago

diketahui akar akar persamaan kuadrat 2x^2-9x + 7 = 0 adalah x1 dan x2. nilai dari x1^2 + x2^2- 4x1x2 adalah...

1 answer:

6 0

jika xy = 0 , kemudian menganggap x dan y = 0

faktor 2x^2-9+7
(2x-2)(x-7)=0

2x-2=0
2x=2
x=1

x-7=0
x=7

jika 1 = x1 dan 7 = x2 maka jawabannya adalah 1^2+7^2-4(1)(7)=22

jika 7 = x1 dan 1 = x2 maka jawabannya adalah
7^2+7^2-4(7)(1)=22

jawabannya adalah 22

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Sarah is a computer engineer and manager and works for a software company. She receives a

daser333 [38]

Answer:

a) Number of projects in the first year = 90

b) Earnings in the twelfth year = $116500

Total money earned in 12 years = $969000

Step-by-step explanation:

Given that:

Number of projects done in fourth year = 129

Number of projects done in tenth year = 207

There is a fixed increase every year.

a) To find:

Number of projects done in the first year.

This problem is nothing but a case of arithmetic progression.

Let the first term i.e. number of projects done in first year = $a$

Given that:

$a_4=129\\a_{10}=207$

Formula for $n^{th}$ term of an Arithmetic Progression is given as:

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

Where $d$ will represent the number of projects increased every year.

and $n$ is the year number.

$a_4=129=a+(4-1)d \\\Rightarrow 129=a+3d .....(1)\\a_{10}=207=a+(10-1)d \\\Rightarrow 207=a+9d .....(2)$

Subtracting (2) from (1):

$78 = 6d\\\Rightarrow d =13$

By equation (1):

$129 =a+3\times 13\\\Rightarrow a =129-39\\\Rightarrow a =90$

Number of projects in the first year = 90

b)

Number of projects in the twelfth year =

$a_{12} = a+11d\\\Rightarrow a_{12} = 90+11\times 13 =233$

Each project pays $500

Earnings in the twelfth year = 233 $\times$ 500 = $116500

Sum of an AP is given as:

$S_n=\dfrac{n}{2}(2a+(n-1)d)\\\Rightarrow S_{12}=\dfrac{12}{2}(2\times 90+(12-1)\times 13)\\\Rightarrow S_{12}=6\times 323\\\Rightarrow S_{12}=1938$

It gives us the total number of projects done in 12 years = 1938

Total money earned in 12 years = 500 $\times$ 1938 = $969000

8 0

3 years ago

A 208-yard-long road is divided into 16 parts of equal length. Mr. Ward paints a 4-yard-long strip in each part. How long is the

laila [671]

We have been given that a 208-yard-long road is divided into 16 parts of equal length.

Let us find length of each part.

$\text{Length of each part}=\frac{208}{16}$

$\text{Length of each part}=13$

Length of each part will be 13 yards.

We are told that Mr. Ward paints a 4-yard-long strip in each part.

Now we will subtract length of painted strip from length of each equal part to find length of unpainted strip of each part of the road.

$\text{Length of unpainted strip}=13-4$

$\text{Length of unpainted strip}=9$

Therefore, length of each unpainted strip will be 9 yards.

5 0

3 years ago

BC = 4x + 2 AB = 8x + 8 and AC = 22 Find BC

Scilla [17]

Answer:

BC = 6.8

Step-by-step explanation:

The distance from A to B, then from B to C, is the same distance as from A to C.

Thus,

AB + BC = AC

AB = 8x + 8

BC = 4x + 2

AC = 22

AB + BC = AC

(8x + 8) + (4x + 2) = 22

Expanding the parenthesis:

8x + 8 + 4x + 2 = 22

8x + 4x + 8 + 2 = 22

12x + 12 = 22

Subtracting 12 from both sides:

12x = 10

Dividing both sides by 12:

x = 10/12 = 1.2

x = 1.2

We're looking for BC. As we know,

BC = 4x + 2

Let's now put in x = 1.2 into this equation:

BC = 4x + 2

BC = 4 * 1.2 + 2

Since 4 * 1.2 is 4.8:

BC = 4.8 + 2

BC = 6.8

Answer: BC = 6.8

8 0

3 years ago

What is the product of 1/2x-1/4 and 5^2-2x+6 Show work please need an answer fast

kaheart [24]

1/8 for the first one and second one is 23 times 6

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3 years ago

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storchak [24]

Answer:

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Step-by-step explanation:

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3 years ago