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Radda [10]
3 years ago
6

Complete the steps for solving 7 = –2x2 + 10x.

Mathematics
1 answer:
frutty [35]3 years ago
8 0

Answer:

<em>x = ( √11 + 5 ) / 2, and x = ( - √11 + 5 ) / 2</em>

Step-by-step explanation:

Let us solve by completing the square;

7 = - 2x^2 + 10x, ⇒ Switch sides,

- 2x^2 + 10x = 7, ⇒ Divide both sides by - 2,

x^2 - 5x = - 7 / 2, ⇒ Write the equation in the form x^2 + 2ax+ a^2, ( x + a )^2, solving for the value of a,

2ax = - 5x,

a = - 5x / 2x,

a = - 5 / 2, ⇒ Add a^2 ⇒ ( - 5 / 2 )^2 to either side of equation,

x^2 - 5x +  ( - 5 / 2 )^2 = - 7 / 2 + ( - 5 / 2 )^2, ⇒ Simplify,

( x - 5 / 2 )^2 = 11 / 4,

| x - 5 / 2 | = √ ( 11 / 4 ), Solve for value( s ) of x,

<em>Answer; x = ( √11 + 5 ) / 2, and x = ( - √11 + 5 ) / 2</em>

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erik [133]
Fairly straightforward question. She works 30 days and is late 80% or 0.8
We can model our equation
Num days late = late percentage * num working days
Basically fine portion of working days that she was late.

Num days late = 0.8 * 30=24

So Deborah was late 24 out of 30 working days. Would appreciate a brainliest
8 0
2 years ago
Find the first term and common ratio for the geometric sequence a2 =2.5,a4=62.5
fenix001 [56]

Answer:

a1 = 0.5; common ratio = 5

Step-by-step explanation:

Let the common ratio = r

a2 = 2.5

a3 = 2.5r

a4 = 2.5r * r = 2.5r^2

We are told a4 = 62.5, so

2.5r^2 = 62.5

Divide both sides by 2.5

r^2 = 25

r = 5

a2 = a1 * r

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Answer: a1 = 0.5; common ratio = 5

6 0
3 years ago
Multiplying or dividing two related quantities by the same number is called; what?
tamaranim1 [39]
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3 years ago
In these number grids, two numbers are added to give the number below.
lilavasa [31]

Answer:

11, 15, 20

Step-by-step explanation:

there \: would \: be \: 11 \: between \: 4 \: and \: 9 \\ 4 + 11 = 15 \\ 11 + 9 = 20 \\ 20 + 15 = 35 \\  \: please \: rate \: brainliest

5 0
2 years ago
Read 2 more answers
Nora and Lila are reading the same novel for book club. Nora is on page 128 and plans to read 8 pages per day until the next clu
REY [17]

Answer:

Both will be at the same page after 6.5 days and the page number will be 180.

Step-by-step explanation:

Let after x days Nora and Lila will be at the same page.

Nora is on page 128 and plans to read 8 pages per day until the next club meeting.

After x days Nora will be at the page number = 128 + 8x

Similarly, Lila is on page 102 and she reads 12 pages per day.

After x days Lila will be on page number = 102 + 12x

Since after x days they will be at the same page

Therefore, 128 + 8x = 102 + 12x

12x - 8x = 128 - 102

4x = 26

x = \frac{26}{4}

x = 6.5 days

Page number they will be on = 128 + 8(6.5)

= 128 + 52

= 180

Both will be at the same page after 6.5 days and the page number will be 180.

3 0
3 years ago
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