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4 years ago

2x^2 - 3x - 15 = 5 using quadratic equation

Mathematics

1 answer:

Damm [24]4 years ago

4 0

Answer:

x= 4, 2.5(or 5/2)

Step-by-step explanation:

2x²-3x-15=5

-5 -5

2x²-3x-20=0

plug into quadratic equation

(3+13)/4 (3-13)/4

16/4=4 10/4=2.5

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Can someone please do number 30.

Mamont248 [21]

$To\ find\ b\ you\ have\ to\ put\ (2,6)\ into\ second\ eqution:\\\\y=2.5x+b\\\\6=2.5\cdot2+b\\6=5+b\\6-5=b\\b=1\\\\b\ have\ to\ be\ equal\ 1.$

6 0

4 years ago

Solve the system of equations.

guajiro [1.7K]

Answer:

<u>Option b. (x = 3, y = 20, z = -14)</u>

Step-by-step explanation:

Given:

2x + 2y + 3z = 4

5x + 3y + 5z = 5

3x + 4y + 6z = 5

Solve using Cramer’s rule

∴ $\left[\begin{array}{ccc}2&2&3\\5&3&5\\3&4&6\end{array}\right] =\left[\begin{array}{ccc}4\\5\\5\end{array}\right]$

∴A = $\left[\begin{array}{ccc}2&2&3\\5&3&5\\3&4&6\end{array}\right] = -1$

Ax = $\left[\begin{array}{ccc}4&2&3\\5&3&5\\5&4&6\end{array}\right] = -3$

Ay = $\left[\begin{array}{ccc}2&4&3\\5&5&5\\3&5&6\end{array}\right] =-20\\$

Az = $\left[\begin{array}{ccc}2&2&4\\5&3&5\\3&4&5\end{array}\right] = 14$

∴ x = Ax/A = -3/-1 = 3

y = Ay/A = -20/-1 = 20

z = Az/A = 14/-1 = -14

<u>So, the answer is option b. (x = 3, y = 20, z = -14)</u>

4 0

4 years ago

Will mark brainliest

maw [93]

Answer:

Step-by-step explanation:

Surface area = 2wl + 2lh + 2hw

$10\frac{5}{6} * 8\frac{1}{3}*2\\10\frac{5}{6} * 12\frac{1}{2} * 2\\8\frac{1}{3} * 12\frac{1}{2} * 2\\$

180.555555556 + 270.833333334 + 208.333333334 = 659.722222224

ROUNDED = 659.7 $yd^{2}$

PLEASE MARK BRAINLIEST!

7 0

4 years ago

Of the 50 student in the cafeteria, 7 have red hair. If there are 750 students in the school, predict the number of students who

SVEN [57.7K]

Given data,

Of the 50 students in the cafeteria

7 have red hair.

Total number of students = 750

To find:

The proportion that could be used to predict the number of students who have red hair.

Let us assume the number of students who have red hair = x

The ratio of student having red hair to the total number of students are

$Ratio (1) = \frac{7}{50}$

$Ratio (2) = \frac{x}{750}$

The number of students having red hair is proportional to the total number of students. So, the above ratios are equal.

$\frac{x}{750} = \frac{7}{50}$

Cross multiplication,

50x = 7 * 750

50x = 5250

x = 5250/50

x = 105

Therefore,

The required equation is $\frac{x}{750} = \frac{7}{50}$ and the number of students who have red hair is 105.

Learn more about event correlation here: brainly.com/question/10831881

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4 0

1 year ago

If the average, mode, and range of 5 different numbers are all 8, find the sum of all possible values of the second largest numb

ANTONII [103]

I believe you meant:

If the average, mode, and range of 5 different numbers are all 8, find the sum of all possible values and the second largest number

Answer:

Sum of all possible values = 40

Second largest number= 8

Explanation:

Since our mean, mode, and range is 8, our sum is 40 and our second largest number is 8.

The sum of all the numbers is 40 since our mean is 8 and there are 5 numbers(8×5)

To find possible values, we already know the mode is 8 and so we know 8 must appear more than once. If we have 8 twice then we are left with 24(sum is 40). We have 3 numbers left and the range is 8 so we must have a maximum number and minimum number that has a difference of 8 and a third number, all adding up to 24(sum left). Within 24, only 12-4+8 satisfies the condition, hence our numbers are: 4,8,8,8,12.

3 0

3 years ago