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Anvisha [2.4K]
3 years ago
11

Solve 169x^2-42.25=0 by using square roots? NEED HELP!!!

Mathematics
1 answer:
jekas [21]3 years ago
5 0

Answer:

x = 1/2 , x = -1/2

Step-by-step explanation:

Given equation;

169x² - 42.25

Find:

Solution of equation using square root

Computation:

169x² - 42.25

We know that 13² = 169 and 6.5² = 42.25

So,

[13x]² - [6.5]²

a² - b² = (a + b)(a - b)

So,

[13x]² - [6.5]² = [13x + 6.5][13x - 6.5]

So,

13x + 6.5 = 0 , 13x - 6.5 = 0

x = 6.5 / 13 , x = -6.5 / 13

x = 1/2 , x = -1/2

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It takes 15 minutes to preheat your oven to 325 degrees. For an oven preheated to 325 degrees, the recommended cooking time for
Alisiya [41]

Answer:

(a) T = (15 + 16p) minutes

(b) It will takes approximately 239 minutes to prepare a turkey weighing 14 pounds

Step-by-step explanation:

(a) To determine the total time T needed to preheat the oven and then bake a turkey weighing p pounds

We will sum the time needed to preheat the oven to the time needed to bake the turkey.

From the question,

It takes 15 minutes to preheat the oven to 325 degrees;

Also,

It takes 16 minutes per pound to bake a turkey in the preheated oven.

That is, to bake a turkey weighing p pounds in the preheated oven, it will take

p pounds × 16 minutes / pound = 16p minutes

Hence, the total time T needed to preheat the oven and then bake a turkey weighing p pounds is

T = 15 minutes + 16p minutes

T = (15 + 16p) minutes

This is the formula that express the total time T, in minutes, needed to preheat the oven and then bake a turkey

(b) To find the approximate time required to prepare a turkey weighing 14 pounds.

From the formula in (a)

T = (15 + 16p) minutes

where p is the weight in pounds of a turkey

Then,

T = 15 + 16(14)

T = 15 + 224

T = 239 minutes

Hence, it will takes approximately 239 minutes to prepare a turkey weighing 14 pounds

7 0
3 years ago
Simplify (2n + 5) - (3n + 7) + (4n - 9).<br> -3n - 11<br> 3n - 11<br> -3n + 11<br> 3n + 11
Natasha2012 [34]

Answer:

(B) 3n - 11

Step-by-step explanation:

(2n + 5) - (3n + 7) + (4n - 9) = 2n + 5 - 3n - 7 +4n - 9 = 3n  - 11

3 0
3 years ago
Change the decimal into a %:0.7
Tomtit [17]
Simply multiply 0.7 by 100. 0.7 x 100= 70%. The answer is 70%
8 0
3 years ago
Read 2 more answers
How do i solve this
laila [671]
The ratio is 2:3 for the side lengths of the triangles.

so 6:9 is one side and 5:x would be the other side

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4 0
4 years ago
The school store opened on the first day of school with 45 notebooks and 15 pencils. Within two days it sold all of these items.
malfutka [58]

The number of pencils sold on the first day  is 5 pencils.

The number of notebooks sold on the first day  is 10 notebooks.

The number of pencils sold on the second day 10 pencils.

The number of notebooks sold on the second day   35 notebooks.

<u>Step-by-step explanation:</u>

Given data,

  • The total number of notebooks in the store = 45 notebooks.
  • The total number of Pencils in the store = 15 pencils.
  • The number of days that all items were sold = 2 days.

Now, you have to calculate the no.of notebooks and no. of pencils sold each day.

<u>In the first day :</u>

The number of sale of notebooks and pencils are given by,

Twice as many notebooks were sold as pencils.

Let us take, the number of pencils sold on the first day  = x

And,  the number of notebooks sold on the first day  = 2x (Twice as pencils).

<u>In the second day :</u>

The number of sale of notebooks and pencils are given by,

For every 7 notebooks​ sold, 2 pencils were sold.

The number of pencils sold on the second day =   2y

The number of notebooks sold on the second day   = 7y

<u> The equation is framed for number of notebooks sold on each day :</u>

The number of notebooks sold ⇒ 2x + 7y = 45   -------(1)

<u> The equation  is framed for number of pencils sold on each day :</u>

The number of pencils sold: x + 2y = 15  ----------(2)

Solving the equations by multiplying eq(2) by 2 and subtract it from eq(1),

  2x + 7y = 45

-<u> (2x + 4y) = 30</u>

   <u>        3y = 15  </u>

⇒ y = 15/3

⇒ y = 5

The value of y is 5.

Substitute y=5 in eq (2),

⇒ x + 2(5) = 15

⇒ x + 10 = 15

⇒ x = 15 - 10

⇒ x = 5

The value of x is 5.

First day sale,

The number of pencils sold on the first day  = x ⇒ 5 pencils

The number of notebooks sold on the first day  = 2x ⇒ 10 notebooks

Second day sale,

The number of pencils sold on the second day =   2y ⇒ 10 pencils

The number of notebooks sold on the second day   = 7y ⇒ 35 notebooks.

8 0
3 years ago
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