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3 years ago

Can anyone help me solve this?

Mathematics

1 answer:

irina1246 [14]3 years ago

8 0

Uuhjdnxnnxnxncndndtyttygy

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Find the value of x.

PIT_PIT [208]

Answer:

Step-by-step explanation:

180 = 7x +2 + 7x + 2 + 180 - (17x -23)

180 = 14x +4 + 180 -17x +23

180 = -3x +207

3x = 27

x = 9

4 0

2 years ago

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

Si f(1)=18 que es f(5)

alexira [117]

F(5)=90 pienso que si

3 0

3 years ago

How many times does seven go into three hundred ninety four

Nookie1986 [14]

Answer: 56 times.

Step-by-step explanation:

394/7 = 56.3

56 * 7 = 392

392 + 7 = 399

399 is more than 394, therefore the answer is 56.

6 0

2 years ago

Read 2 more answers

A forest covers 43,000 acres. A survey finds that 0.2% of the forest is old-growth trees. How many acres of old-growth trees are

Gelneren [198K]

Answer:

8,600 acres are old-growth trees.

Step-by-step explanation:

You can find this by multiplying the percentage by the overall number of acres

20% * 43,000 = 8,600

5 0

3 years ago

Read 2 more answers