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3 years ago

Solve −3x2 + 30x − 90 = 0

Mathematics

1 answer:

Ray Of Light [21]3 years ago

6 0

Step-by-step explanation:

so, it is a quadratic equation :

-3x² + 30x - 90 = 0

the first thing we can do is divide by 3

-x² + 10x - 30 = 0

remember, the formula to solve and find the 2 solutions is

x = (-b ± sqrt(b² - 4ac))/(2a)

in our case here

a = -1

b = 10

c = -30

x = (-10 ± sqrt(100 - 4×-1×-30))/-2 =

= (-10 ± sqrt(100 - 120))/-2 = (-10 ± sqrt(-20))/-2 =

= (-10 ± sqrt(4×5)i)/-2 = (-10 ± 2×sqrt(5)i)/-2 =

= 5 ± -sqrt(5)i

x1 = 5 - sqrt(5)i

x2 = 5 + sqrt(5)i

remember, i = sqrt(-1), a complex number.

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Matthew brought 7 candy bars that cost $1.20 each.He paid with 9 one - dollar bills. How much change did Matthew receive?

aliina [53]

7*$1.20=$8.40
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answer is $0.60

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3 years ago

is it better to buy 3 gifts and get one free or use a coupon for 20% off of three. which is cheaper i’m too lazy to do it :~|

FrozenT [24]

Answer:

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Step-by-step explanation:

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3 years ago

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Will mark brainliest

VMariaS [17]

Answer:

Interquartile range => 7

Third quartile => 22

Range => 13

First quartile => 15

Step-by-step explanation:

Order your data set, from the least amount to the highest amount:

$12, $14, $15, $15, $15, $15, $16, $22, $24, $25

Interquartile range (IQR) = third quartile (Q3) - first quartile (Q1)

Q1 = the middle value of the lower part of the data set, from the median to your left.

Q3 = the middle value of the upper part of the data set, from the median to your right.

The median lies between the 5th and 6th value that is enclosed in the parenthesis below:

$12, $14, ($15), $15, $15,[Median], $15, $16, ($22), $24, $25

The median divides the data set into upper and lower part.

Median = $\frac{15 + 15}{2} = 15$

First quartile: Q1 = $15

Third quartile: Q3 = $22

IQR = $22 - $15 = $7

Range = highest amount - least amount = 25 - 12 = $13

3 0

4 years ago

the first box measures 18 inches by 8 inches by 15 inches. the second box is 10 inches tall and the area of the base measures 19

Mandarinka [93]

Answer:

Box 1 has the greater volume, by 200 in³

Step-by-step explanation:

The largest of two volumes can be found by computing each volume and comparing the results.

The volume is computed from dimensions by ...

V = LWH

V = (18 in)(8 in)(15 in) = 2160 in³

The volume is computed from area and height by ...

V = Bh . . . . . where B is the base area, and h is the height

V = (196 in²)(10 in) = 1960 in³

<h3>Comparison</h3>

The units of the two volumes are the same, so we can decide which is larger by comparing the numbers. Box 1 has a volume that is more than 2000 in³, and Box 2 has a volume that is less than 2000 in³.

Box 1 has a greater volume

The amount by which the volume is greater can be found by subtracting the smaller volume from the larger:

2160 in³ -1960 in³ = 200 in³

Box 1 is larger by 200 in³

_____

<em>Additional comment</em>

The percentage by which Box 1 is larger than Box 2 can be found by multiplying 100% by the ratio of the difference to the Box 1 volume:

200/1960 × 100% ≈ 10.2%

Box 1 is about 10% larger than Box 2.

3 0

2 years ago

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I need help fr!! ignore the writing lol

Romashka [77]

Answer:

-40

Step-by-step explanation:

(-7)(5)-5=-35-5=-40

8 0

2 years ago

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