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2 years ago

Anybody ????? I will mark you brainliest

Mathematics

2 answers:

Over [174]2 years ago

6 0

I think the answer is B

lesya [120]2 years ago

4 0

The answer is B ....

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If the sum of the zereos of the quadratic polynomial is 3x^2-(3k-2)x-(k-6) is equal to the product of the zereos, then find k?

lys-0071 [83]

Answer:

Step-by-step explanation:

So I'm going to use vieta's formula.

Let u and v the zeros of the given quadratic in ax^2+bx+c form.

By vieta's formula:

1) u+v=-b/a

2) uv=c/a

We are also given not by the formula but by this problem:

3) u+v=uv

If we plug 1) and 2) into 3) we get:

-b/a=c/a

Multiply both sides by a:

-b=c

Here we have:

a=3

b=-(3k-2)

c=-(k-6)

So we are solving

-b=c for k:

3k-2=-(k-6)

Distribute:

3k-2=-k+6

Add k on both sides:

4k-2=6

Add 2 on both side:

4k=8

Divide both sides by 4:

k=2

Let's check:

$3x^2-(3k-2)x-(k-6) \text{ with }k=2$ :

$3x^2-(3\cdot 2-2)x-(2-6)$

$3x^2-4x+4$

I'm going to solve $3x^2-4x+4=0$ for x using the quadratic formula:

$\frac{-b\pm \sqrt{b^2-4ac}}{2a}$

$\frac{4\pm \sqrt{(-4)^2-4(3)(4)}}{2(3)}$

$\frac{4\pm \sqrt{16-16(3)}}{6}$

$\frac{4\pm \sqrt{16}\sqrt{1-(3)}}{6}$

$\frac{4\pm 4\sqrt{-2}}{6}$

$\frac{2\pm 2\sqrt{-2}}{3}$

$\frac{2\pm 2i\sqrt{2}}{3}$

Let's see if uv=u+v holds.

$uv=\frac{2+2i\sqrt{2}}{3} \cdot \frac{2-2i\sqrt{2}}{3}$

Keep in mind you are multiplying conjugates:

$uv=\frac{1}{9}(4-4i^2(2))$

$uv=\frac{1}{9}(4+4(2))$

$uv=\frac{12}{9}=\frac{4}{3}$

Let's see what u+v is now:

$u+v=\frac{2+2i\sqrt{2}}{3}+\frac{2-2i\sqrt{2}}{3}$

$u+v=\frac{2}{3}+\frac{2}{3}=\frac{4}{3}$

We have confirmed uv=u+v for k=2.

4 0

2 years ago

What is the answer to 2/5x+3/7=1-4/7x

skelet666 [1.2K]

X=10/17 thats ur answer

7 0

3 years ago

Ricky has gone through 24 pencils in the past three months. At this rate, how many pencils will Ricky go through in seven months

wlad13 [49]

Ricky will go through 56 pencils in seven months

3 0

3 years ago

Read 2 more answers

If you pay $35 for a drug and the selling price is $50 what is the mark-up of this drug

Daniel [21]

Answer:

15$

Step-by-step explanation:

15$

3 0

2 years ago

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If if Spencer spent a total of $704.00 in the month of July, which is the best estimate for the amount of money he spent on clot

Maksim231197 [3]

Answer:

$Clothing = \$190.0$

Step-by-step explanation:

Given [Missing details]

Spencer's expenses

$Clothing = 27\%$

$Gasoline = 11\%$

$Food = 44\%$

$Entertainment = 18\%$

$Total= \$704.00$

Required:

An estimate for the amount spent on clothing

To do this, simply multiply the clothing percentage by the total amount.

$Clothing = 27\% * \$704.00$

$Clothing = 0.27 * \$704.00$

$Clothing = \$190.08$

Approximate

$Clothing = \$190.0$

6 0

3 years ago