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Katen [24]
3 years ago
14

Solve -2x^2 + 10x + 9 =0 by using completing the squares and give u r answer to two decimal places

Mathematics
2 answers:
adell [148]3 years ago
3 0
<span>-2x^2 + 10x + 9 =0
multiply whole equation by -1
2x^2  -10x -9 =0

(sqrt2x)^2  -2(sqrt2x)(5/</span>sqrt2) -9=0
add (5/sqrt2)^2 on both sides
(sqrt2x)^2  -2(sqrt2x)(5/sqrt2) + (5/sqrt2)^2-9=(5/sqrt2)^2

a^2-2ab+b^2=(a-b)^2
(sqrt2x  -  5/sqrt2)^2=(5/sqrt2)^2+9

(sqrt2x  -  5/sqrt2)^2=21.5

taking squareroot on both sides

sqrt2x  -  5/sqrt2 = +-4.64
so
sqrt2x  -  5/sqrt2 = +4.64       or         sqrt2x  -  5/sqrt2 = -4.64
sqrt2x = 4.64 +  5/sqrt2                     sqrt2x = -4.64 +  5/sqrt2
sqrt2x =8.18                                         sqrt2x = -1.1045
x=8.18/sqrt2                                        x= -1.1045/sqrt2
x=5.78                                                 x=-0.781
Tamiku [17]3 years ago
3 0
The picture above is the answer if you have any question, feel free to ask and if not it would be nice if you give me a brainliest answer :)

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san4es73 [151]
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8 0
3 years ago
4 times x with an exponent of 2 plus 2 times y with an exponent of 4. X=-3 y=2
Digiron [165]

Answer:

Step-by-step explanation:

Your equation is: 4*x^{2} +2 * y^{4}

You also know that x = -3 and y = 2. You can rewrite the equation by substituting x and y with their actual values:

4*(-3)^{2} +2 * 2^{4}

First, you want to do the exponentiation (meaning you want to calculate (-3)^{2} and 2^{4} parts). (-3)^{2} equals 9 and 2^{4} equals 16.

So the equation now is:

4*9+2*16

Now you want to do multiplication. 4*9 equals 36 and 2*16 equals 32. So you're left with:

36+32

Which equals 68.

8 0
3 years ago
Janine is packing carrots. Each large box holds 20 2-pound bags of carrots. If janine has 800 bags of carrots, how many boxes ca
grigory [225]
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5 0
3 years ago
Read 2 more answers
Describe two to evaluate 37% of the sum of 27 and 3/5 and 15.9
zhuklara [117]
First way is to first find the sum and then find 37% of it. Second way is another way round, find 37 of 27 3/5 and 37% of 15.9 and then add it.

Lets do it
37%=0.37
- its the result
Second way its
0.37* 27 3/5 + 0.37*15.9=10.212 + 5.888=16.095
7 0
3 years ago
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