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2 years ago

7

:) :( :) ;) ;( ;) ;)

2 answers:

pshichka [43]2 years ago

8 0

What does it means hello

SSSSS [86.1K]2 years ago

6 0

Answer:

um

Step-by-step explanation:

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2x^3-x^2-3x=210<br> the answer is 5 but I want to know why.

mel-nik [20]

Answer:

$x=5,\frac{-9+\sqrt{255}i }{4} ,\frac{-9-\sqrt{255}i }{4}$

Step-by-step explanation:

1) Move all terms to one side.

$2x^{3} -x^{2} -3x-210=0$

2) Factor $2{x}^{3}-{x}^{2}-3x-210$ using Polynomial Division.

1 - Factor the following.

$2x^{3} -x^{2} -3x-210$

2 - First, find all factors of the constant term 210.

$1,2,3,4,5,6,7,10,14,15,21,30,35,42,70,105,210$

3) Try each factor above using the Remainder Theorem.

Substitute 1 into x. Since the result is not 0, x-1 is not a factor..

$2*1^{3} -1^{2} -3*1-210=-212$

Substitute -1 into x. Since the result is not 0, x+1 is not a factor..

$2(-1)^{3} -(-1)^{2} -3*-1-210=-210$

Substitute 2 into x. Since the result is not 0, x-2 is not a factor..

$2*2^{3} -2^{2} -3*2-210=-204$

Substitute -2 into x. Since the result is not 0, x+2 is not a factor..

$2{(-2)}^{3}-{(-2)}^{2}-3\times -2-210 = -224$

Substitute 3 into x. Since the result is not 0, x-3 is not a factor..

$2\times {3}^{3}-{3}^{2}-3\times 3-210 = -174$

Substitute -3 into x. Since the result is not 0, x+3 is not a factor..

$2{(-3)}^{3}-{(-3)}^{2}-3\times -3-210 = -264$

Substitute 5 into x. Since the result is 0, x-5 is a factor..

$2\times {5}^{3}-{5}^{2}-3\times 5-210 =0$

------------------------------------------------------------------------------------------

⇒ $x-5$

4) Polynomial Division: Divide $2{x}^{3}-{x}^{2}-3x-210$ by $x-5$ .

$2x^{2}$ $9x$ $42$

-------------------------------------------------------------------------

$x-5$ | $2x^{3}$ $-x^{2}$ $-3x$ $-210$

$2x^{3}$ $-10x^{2}$

-----------------------------------------------------------------------

$9x^{2}$ $-3x$ $-210$

--------------------------------------------------------------------------

$42x$ $-210$

$42x$ $-210$

-------------------------------------------------------------------------

5) Rewrite the expression using the above.

$2x^2+9x+42$

$(2x^2+9x+42)(x-5)=0$

3) Solve for $x.$

$x=5$

4) Use the Quadratic Formula.

1 - In general, given $a{x}^{2}+bx+c=0$ , there exists two solutions where:

$x=\frac{-b+\sqrt{b^{2} -4ac} }{2a} ,\frac{-b-\sqrt{b^2-4ac} }{2a}$

2 - In this case, $a=2,b=9$ and $c = 42.$

$x=\frac{-9+\sqrt{9^2*-4*2*42} }{2*2} ,\frac{-9-\sqrt{9^2-4*2*42} }{2*2}$

3 - Simplify.

$x=\frac{-9+\sqrt{255}i }{4} ,\frac{-9-\sqrt{255}i }{4}$

5) Collect all solutions from the previous steps.

$x=5,\frac{-9+\sqrt{255}i }{4} ,\frac{-9-\sqrt{255}i }{4}$

4 0

1 year ago

Read 2 more answers

4/7 is the result when 1/2 and x are added.

kipiarov [429]

By solving the equation
1/2 +x =4/7
x = 4/7 -1/2
x= 1/14

5 0

2 years ago

the probability of a basketball player hitting a foul shot is 1/3. how many shots would you expect her to make in 90 attempts?

Kaylis [27]

90 attempts are made and only one third are successful. Multiply the attempts by successes and you get 30 successful shots (90 x 1/3= 30).

8 0

2 years ago

Read 2 more answers

Find the direction angle of 3i+1j.<br><br> Please help me. Thank you

Alekssandra [29.7K]

Answer:

Correct answer: ∝ = 18.43°

Step-by-step explanation:

Given coordinates represent one vector in x-y plane, let be v.

v = 3i +1j = xi + yj => x = 3 and y = 1

The angle that this vector builds with the positive direction to the x axis will be found using the tangent.

∝ = tan⁻¹ y/x = tan⁻¹ 1/3 = tan⁻¹ 0.333 = 18.43°

∝ = 18.43°

God is with you!!!

4 0

2 years ago

5x+3y=17 x+y=4 substitution

solmaris [256]

Group the xs and the ys, 17+5= 22x 3+1=4y so y=4 and x=22.

4 0

1 year ago