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2 years ago

7

A classroom measures 12 meters long and 9 meters wide. When using a scale of 1 cm to 1.5 m to draw the room on your paper, the s

ize would be

1 answer:

Tema [17]2 years ago

6 0

12m(cm/1.5m) by 9m(cm/1.5m)

8cm by 6cm

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The square of a number decreased by 3 times the number 28 find all possible values for the number

stealth61 [152]

Question:

The square of a number decreased by 3 times the number is 28 find all possible values for the number

Answer:

The possible values of number are 7 and -4

Solution:

Given that the square of a number decreased by 3 times the number is 28

To find: all possible values of number

Let "a" be the unknown number

From given information,

square of a number decreased by 3 times the number = 28

$a^2 - 3a = 28$

$a^2 - 3a - 28 = 0$

Let us solve the above quadratic equation

$\text {For a quadratic equation } a x^{2}+b x+c=0, \text { where } a \neq 0$

$x=\frac{-b \pm \sqrt{b^{2}-4 a c}}{2 a}$

Using the above formula,

$\text { For } a^{2}-3 a-28=0 \text { we have } a=1, b=-3, c=-28$

$\begin{aligned}&a=\frac{-(-3) \pm \sqrt{(-3)^{2}-4(1)(-28)}}{2 \times 1}\\\\&a=\frac{3 \pm \sqrt{9+112}}{2}\\\\&a=\frac{3 \pm \sqrt{121}}{2}=\frac{3 \pm 11}{2}\\\\&a=\frac{3+11}{2} \text { or } a=\frac{3-11}{2}\\\\&a=7 \text { or } a=-4\end{aligned}$

Thus the possible values of number are 7 and -4

5 0

2 years ago

The area of the figure

STALIN [3.7K]

Rectangle:

4*8=32

Semicircle:

3.14*4^2= 50.24
50.24/2=25.12

Add:

25.12+32= 57.12

Final answer: A

5 0

2 years ago

Read 2 more answers

A rectangular prism has a volume of 320 cubic cm. Its height is 8 cm. What is the area of its base? A 40 square cm B 4 square cm

Airida [17]

Volume of a prism is height x base x length. the area of the base would be calculated from the volume/ height so
320/8 = 40 cm squared

3 0

1 year ago

Find the cube root of 27d3 + 54a2b + 36ab2 + 8b3

enot [183]

Answer:

(3a + 2b)3

Step-by-step explanation:

STEP 1 :

Equation at the end of step 1

(((27•(a3))+((54•(a2))•b))+(36a•(b2)))+23b3

Step 2:

(((27•(a3))+((54•(a2))•b))+(22•32ab2))+23b3

Step 3:

(((27•(a3))+((2•33a2)•b))+(22•32ab2))+23b3

Step 4:

((33a3 + (2•33a2b)) + (22•32ab2)) + 23b3

Step 5:

Factoring: 27a3+54a2b+36ab2+8b3

8 0

1 year ago

One hundred teachers attended a seminar on mathematical problem solving. The attitudes of representative sample of 12 of the tea

andrew11 [14]

Answer:

a) 1.92

b) 3.25

c) 1.5

d) -5.23

Step-by-step explanation:

We are given the following in the question:

4, 7, -1, 1, 0, 5, -2, 2, -1, 6, 5, -3

a) mean of score change

$Mean = \displaystyle\frac{\text{Sum of all observations}}{\text{Total number of observation}}$

$Mean =\displaystyle\frac{23}{12} = 1.92$

b) standard deviation for this population

$\text{Standard Deviation} = \sqrt{\displaystyle\frac{\sum (x_i -\bar{x})^2}{n}}$

where $x_i$ are data points, $\bar{x}$ is the mean and n is the number of observations.

Sum of squares of differences = 126.92

$\sigma = \sqrt{\frac{126.92}{12}} = 3.25$

c) median change score

$Median:\\\text{If n is odd, then}\\\\Median = \displaystyle\frac{n+1}{2}th ~term \\\\\text{If n is even, then}\\\\Median = \displaystyle\frac{\frac{n}{2}th~term + (\frac{n}{2}+1)th~term}{2}$

Sorted data: -3, -2, -1, -1, 0, 1, 2, 4, 5, 5, 6, 7

Median =

$\dfrac{6^{th} + 7^{th}}{2} = \dfrac{1+2}{2} = 1.5$

d) change score that is 2.2 standard deviations below the mean.

$x = \mu - 2.2(\sigma)\\x = 1.92-2.2(3.25)\\x = -5.23$

4 0

1 year ago