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n200080 [17]
2 years ago
9

Solve the polynomial equation by factoring. x^3+2x^2-9x-18=0

Mathematics
1 answer:
lyudmila [28]2 years ago
3 0

Answer:

This can be factored to (x + 3)(x - 3)(x + 2) = 0

So x is equal to 3, -3 and -2

Step-by-step explanation:

x³ + 2x² - 9x -18 = 0

Let's try dividing by (x + 3) as that looks like it might be a factor.  We'll use long division:

                    x²  - x - 6

        x + 3  }  x³ + 2x² - 9x -18

                    x³ + 3x²

                           -x² - 9x

                           -x² - 3x

                                -6x - 18

                                -6x - 18

                                         0

Perfect!  So (x + 3) is a factor, giving us:

(x + 3)(x² - x - 6)

the remaining quadratic can be factored more easily:

(x + 3)(x² - x - 6)

= (x + 3)(x² + 2x - 3x - 6)

= (x + 3)(x[x + 2] - 3[x + 2])

= (x + 3)(x - 3)(x + 2)

Now we can solve it easily as we know that's equal to zero, so x can be equal to 3, -3, and -2

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The vertex of the graph of y = -4(x + 3)² + 2 is<br> DONE
wariber [46]

A parabola is a mirror-symmetrical planar curve that is nearly U-shaped. The vertex of the parabola will lie at (-3,2).

<h3>What is the Equation of a parabola?</h3>

A parabola is a mirror-symmetrical planar curve that is nearly U-shaped.

y = a(x-h)² + k

where,

(h, k) are the coordinates of the vertex of the parabola in the form (x, y);

a defines how narrower is the parabola, and the "-" or "+" that the parabola will open up or down.

Comparing the given equation with the equation of a parabola, we will get,

y =  a(x -h)² + k

y = -4(x+3)² + 2

Hence, the vertex of the parabola will lie at (-3,2).

Learn more about Parabola:

brainly.com/question/8495268

#SPJ1

5 0
2 years ago
Please help, very confused
miss Akunina [59]

Answer:

1.

-3x + 8y = -5

6x + 2y = -8

Set the equations to a common variable.

-3x + 8y = -5 → 8y = 3x - 5 → y = 3/8x - 5/8

6x + 2y = -8 → 2y = -6x - 8 → y = -3x - 4

Set the equations equal to each other.

3/8x - 5/8 = -3x - 4

Combine like terms.

3x + 3/8x = -4 + 5/8

3.375x = -3.375

Divide by 3.375

x = -1

Plug x back in to find y.

-3x + 8y = -5

-3(-1) + 8y = -5

3 + 8y = -5

8y = -8

y = -1

answer: (-1, -1)

2.

3x + 2y = -16

-3x - 8y = 46

Set the equations to a common variable.

3x + 2y = -16 → 2y = -3x - 16 → y = -3/2x - 8

-3x - 8y = 46 → -8y = 3x + 46 → y = -3/8x - 23/4

Set the equations equal to each other.

-3/2x - 8 = -3/8x - 23/4

Combine like terms.

-9/8x = 9/4

or

-1.125x = 2.25

Divide by -1.125

x = -2

Plug x back in to find y.

3(-2) + 2y = -16

-6 + 2y = -16

2y = -10

y = -5

answer: (-2, -5)

6 0
3 years ago
Read 2 more answers
Convert the angle \theta=\dfrac{8\pi}{9}θ=
Olegator [25]

Answer:

160°

Step-by-step explanation:

-Given the angle in radians as \theta=\dfrac{8\pi}{9}\ rad

-We know that  1 \ rad=\frac{180}{\pi}\textdegree

-Let our angle theta be X

#We therefore equate and cross multiply:

1\ rad=\frac{180}{\pi}\\\\\frac{8\pi}{9}=x\\\\\therefore X=\frac{180}{\pi}\times \frac{8\pi}{9}\\\\=160\textdegree

Hence, angle θ is 160°

8 0
2 years ago
Answer this if you can
Soloha48 [4]
The answer is x=y. 

You'll see if you replace all the x's with y's.



6 0
3 years ago
8m + 7 = 5m +16 what is this answer
Sophie [7]
M equals 3.
That's your answer
5 0
2 years ago
Read 2 more answers
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