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3 years ago

What is the value of x (81) (7x+15)

Mathematics

1 answer:

scoray [572]3 years ago

3 0

Answer:

9 if I am correct also I rounded to a whole number, am not sure

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How do I complete this

DochEvi [55]

Answer:i dont know evaluate it

Step-by-step explanation:

3 0

3 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

3 years ago

A group of friends wants to go to the amusement park. They have $469.75 to spend on parking and admission. Parking is $10.75, an

attashe74 [19]

Answer:

Step-by-step explanation:

469.75-10.75 =

459 ÷ 38.25 =

8 0

2 years ago

0.6×8 and tell me how you got the answer pls <img src="https://tex.z-dn.net/?f=0.6%20%5Ctimes%208" id="TexFormula1" title="0.

Tresset [83]

Answer:

4.8 is the answer!

Step-by-step explanation:

0.6 x 8 = 4.8

6 x 8 = 48

multiply 6 by 8, and move the decimal to the left one time, and get 4.8

7 0

3 years ago

Read 2 more answers

Simplify (6 +i)(8 – 3i) 51 – 10i 48 – 32i 45 – 10i 48 – 10i – 3i^2 ...?

mote1985 [20]

= 48 - 18i + 8i - 3i²
= 48 – 10i – 3i²

4 0

3 years ago