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lakkis [162]
2 years ago
8

Solve by completing the square: 4x^2 + 16x +25 =0 x = _ & x = _

Mathematics
1 answer:
12345 [234]2 years ago
7 0
<h2>Answer: ∅</h2>

Step-by-step explanation: When solving by completing the square,

we cannot have a coefficient on the squared term.

So first divide both sides by 4 to get x² + 4x + 25/4 = 0.

Now subtract 25/4 from both sides and leave a space.

So we have x² + 4x ____ = -25/4 ____.

The number that goes in that space is the number needed

to create a perfect square trinomial on the left side.

The question is, what is that number?

Well it comes from a formula.

The number that goes in that space comes from

half the coefficient of the middle term squared.

So that's half of 4 squared or 2 squared which is 4.

So we add 4 to both sides.

On the left, we will get a binomial squared

which will use x and half the coefficient of the middle term.

So we have (x + 2)².

On the right, -25/4 + 16/4 is -9/4.

So we have (x + 2)² = -9/4.

Notice that when take the square root of both sides,

we have the square root of a negative which is illegal.

So we say our answer is ∅.

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kkurt [141]

Answer:

(x- \frac{2}{5})^{2} = x^2 -\frac{4}{5}x + \frac{4}{25}

Step-by-step explanation:

You have two methods to expand this binomial.

Method 1  

If you have the expression:

(x- \frac{2}{5})^{2}

You can write the expression it in the following way:

(x-\frac{2}{5})^{2}=(x-\frac{2}{5})(x-\frac{2}{5})

Then, apply the distributive property:

(x-\frac{2}{5})(x-\frac{2}{5}) = x^2 -\frac{2}{5}x -\frac{2}{5}x+ (\frac{2}{5})\frac{2}{5}

Simplify the expression:

(x-\frac{2}{5})^2= x^2 -\frac{4}{5}x+ (\frac{4}{25})

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

Method 2

For any expression of the form:

(a-b)^2

Its expanded form will be:

(a-b)^2= a^2 -2ab + b^2

If

a = x

b =\frac{2}{5}

(x- \frac{2}{5})^{2} = x^2 - 2x\frac{2}{5} + (\frac{2}{5})^2

(x- \frac{2}{5})^{2} = x^2 -\frac{4}{5}x + \frac{4}{25}

3 0
3 years ago
If the factors of a quadratic function are (x + 2) and (x − 9), what are the x-intercepts of the function?
Zielflug [23.3K]

Answer: D. (-2,0) and (9,0)

Step-by-step explanation:

When you equate the factors to 0 you get

(X+2) = 0

X = -2

(X-9) = 0

X= 9

Here the Y value is 0 as you find the factors of x when the Y value is 0.

So the answer is (-2,0) and (9,0)

8 0
2 years ago
Need answer ASAP <br> *MARKING BRAINLIEST
Luba_88 [7]

Answer:

252 in²

Step-by-step explanation:

Recall area of regular polygon is A= (1/2)*(perimeter)*(apothem)

Area = (1/2)*(63)*(7)

= 252 in²

7 0
3 years ago
Read 2 more answers
In the united states the speed limit signs are in Miles per hour. Unfortunately, your speedometer only reads in km/hour. How man
ohaa [14]

Hello,

1mph = 1.60934kph

70 x 1.60934 = 112.6538

Answer:

70mph = 112.6538kph

8 0
3 years ago
Whats 9 plus 10
Anna11 [10]

Answer:

it is 21 because 9+10=19+2=21-10=11+10=21 its magic

Step-by-step explanation:

5 0
3 years ago
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