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3 years ago

Solve for x in the equation 2x^2-4x-9=29

Mathematics

1 answer:

Andrews [41]3 years ago

3 0

Answer:

x = 1 ±2sqrt(5)

Step-by-step explanation:

2x^2-4x-9=29

Add 9 to each each side

2x^2-4x-9+9=29+9

2x^2-4x=38

Divide by 2

2/2x^2-4/2x=38/8

x^2 -2x =19

Complete the square

x^2 -2x + (-2/2)^2 = 19 +(-2/2)^2

x^2 -2x +1 = 19+1

(x-1)^1=2 = 20

Take the square root of each side

sqrt((x-1)^2) = ±sqrt(20)

x-1 = ±sqrt(20)

Add 1 to each side

x-1+1 = 1 ±sqrt(20)

x = 1 ±sqrt(20)

Simplifying the square root of 20

x = 1 ±sqrt(4)sqrt(5)

x = 1 ±2sqrt(5)

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If a =7 , find the area of it . Please give me the answer I have a exam at 12.00

Sindrei [870]

Answer:

60cm²

Step-by-step explanation:

Area of a rectangle = length x breath

Let,

length (L) = (a-1) cm

breadth (B) = (a+3) cm

Putting the value of a = 7;

we get,

length= 7-1 = 6 cm

breadth= 7+3 = 10 cm

Therefore, area of the rectangle = L x B

= 6 x 10

= 60 cm²

3 0

3 years ago

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Harrison went out to buy coffee for his classmates. There are 23 students in his class, counting Harrison himself. Some wanted m

NemiM [27]

Step-by-step explanation:

Let's represent the number of mochas bought with the variable $M$ , and the number of lattes bought with the variable $L$ .

Since there are $23$ students, the total number of mochas and lattes bought must be $23$ . This can be represented with the following equation:

$M + L = 23$

We can also set up another equation based on the total amount spent on the coffe:

$4.30M + 3.50L = 87.70$

If we rearrange the first equation, we can solve for $M$ :

$M = 23 - L$

If we substitute this into the second equation, we can solve for $L$ :

$4.30(23 - L) + 3.50L = 87.70$

$98.9 - 4.3L + 3.5L = 87.7$

$98.9 - 0.8L = 87.7$

$0.8L = 11.2$

$L = 14$

Subtituting this back into the original equation, we can solve for $M$ :

$M + L = 23$

$M + 14 = 23$

$M = 9$

Therefore, 9 mochas and 14 lattes were bought.

3 0

3 years ago

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Please select the best answer and click submit Solve kx-4=9 for x

shepuryov [24]

Answer:

Option B. $x = \frac{13}{k}$ .

Step-by-step explanation:

The given equation is kx - 4 = 9

We will add 4 on both the sides of the equation

kx - 4 +4 = 9 +4

kx = 13

Now we will divide by k on both the sides of the equation

$\frac{1}{k}(13x) = \frac{1}{k}13$

$x = \frac{13}{k}$

Therefore Option B x = 13/k is the right answer.

6 0

3 years ago

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There were 178 old cars at the junkyard. Then a truck brought in some more cars. Now there are a total of 236 cars in the junkya

crimeas [40]

Answer:

The correct answer is 58 cars.

Step-by-step explanation:

Cars in the junkyard before the truck arrived with some = 178

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Cars brought in by the truck = 236 - 178

Cars brought into the junkyard by the truck = 58

The number of cars brought by the truck is 58 cars.

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4 years ago

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Nookie1986 [14]

Answer:

(3,4)

Step-by-step explanation:

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