4y+3=3y+x; 2x+4y=18 solve using the substitution method

Which expressions are equivalent to {22c + 33d}22c+33d22, c, plus, 33, d?

kotegsom [21]

A
(-2c-3d) (- 11) (- 2c-3d) (- 11) left parenthesis, minus, 2, c, minus, 3, d, right parenthesis, left parenthesis, minus, 11, right parenthesis
C
(66c + 99d) \ cdot \ dfrac {1} {3} (66c + 99d) ⋅ 3
1 left parenthesis, 66, c, plus, 99, d, right parenthesis, dot, start fraction, 1, divided by, 3, end fraction
 E
11\cdot(2c+3d)11⋅(2c+3d)11, dot, left parenthesis, 2, c, plus, 3, d, right parenthesis
 answer
(-2c-3d) (- 11) = 22c + 33d
(66c + 99d) * 1/3 = 22c + 33d
11 * ( 2c+3d) = 22c + 33d

4 0

4 years ago

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Can you please explain to me how to do this please

hram777 [196]

Explanation:

You asked how to do it, so that is the answer we will give. (The question would be "too complex" if you asked for answers to all 18 questions.)

First of all, recognize that angle values are given in degrees for some problems* and radians for other problems. Know that π radians is 180°, so you can convert to degrees by replacing π with 180°.

1. Find the quadrant of the angle:

0 to 90° is Quadrant I

90° to 180° is Quadrant II

180° to 270° is Quadrant III

270° to 360° is Quadrant IV

The signs of the trig functions in the different quadrants are ...

sine -- positive in I and II, negative in III and IV

cosine -- positive in I and IV, negative in II and III

tangent -- positive in I and III, negative in II and IV

__

2. Find the reference angle. The reference angle for angle α is the smallest of ...

|α| or |180° -α| or |360° -α|

It will be a positive number in the range 0° to 90°.

__

3. Make use of the short table of trig function values you have memorized. This gives you the exact value of the reference angle you found in step 2.

sin(0°) = cos(90°) = 0

sin(30°) = cos(60°) = 1/2

sin(45°) = cos(45°) = (√2)/2

sin(60°) = cos(30°) = (√3)/2

sin(90°) = cos(0°) = 1

As always, the tangent is the ratio of sine to cosine, so you have ...

tan(0°) = 0

tan(30°) = (√3)/3

tan(45°) = 1

tan(60°) = √3

tan(90°) = undefined

__

4. Apply the sign of the desired function in the desired quadrant to the value you found in step 3. (For non-zero function values, the sign on a quadrant boundary matches the signs for the quadrants on either side.)

_____

Examples:

cos(225°) = -cos(45°) = -(√2)/2 . . . . (quadrant III, ref angle 45°)
sec(270°) = 1/cos(90°) = 1/0 = undefined . . . . (ref angle 90°)
cot(5π/6) = cot(150°) = 1/-tan(30°) = -√3 . . . . (quadrant II, ref angle 30°)

_____

* Technically, sin 60 should be interpreted as sin(60 radians), since there is no degree symbol present. In this context, we can reasonably assume that values not a multiple of pi will be in degrees. (That may not always be the case.) You should always be careful to specify what unit of measure is being used for angles--even if your curriculum materials are not so careful. Your calculator is very particular on that point.

5 0

3 years ago

What is the value of x? Enter your answer in the box

shusha [124]

The value of x is 1 or number line

8 0

4 years ago

A circle has a circumference of 616 cm.

Ray Of Light [21]

Answer:

π =14 cm

Step-by-step explanation:

Given:

circumference of a circle =616 cm

pie(π)=22/7

circumference of a circle=πr^2

616=22/7 *r^2

616*7/22 =r^2

4312/22 =r^2

196=r^2

$\sqrt{196}$ =r

14 =r

4 0

3 years ago

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A data set of 27 different numbers has a mean of 33 and a median of 33. A new data set is

Svetllana [295]

Answer:

Option D.

Step-by-step explanation:

Suppose that we have a set of N values:

{x₁, x₂, ..., xₙ}

The median is the value in the middle, and the mean is calculated as:

$M = \frac{(x_1 + x_2 + x_3 ... + x_n)}{N}$

Because here we have "the median" then we will assume that N is odd, and there is only one median, the value "k" (if N was even, the median would be the mean of the two middle values, that case is really similar to the case where N is odd, so solving only one of the cases is enough)

Now we add 7 to all the values greater than the median

We subtract 7 to all values smaller than the median.

Then the median remains unchanged (because we did not add nor subtract anything to the median).

The new mean will be:

$M' = \frac{(x_1 - 7) + (x_2 - 7) + ... + (x_{k}) + ... + (x_n + 7)}{N} = \frac{(x_1 + x_2 + ... + x_n) + (-7)*(n/2 - 0.5) + 7*(n/2 - 0.5)}{N} = \frac{(x_1 + x_2 + ... + x_n)}{N} = M$

So the mean does not change.

Because the mean is computed as the sum of the numbers divided by N, and the mean does not change, and N does not change, then the sum of the numbers does not change.

Finally, the standard deviation is computed as:

$SD = \sqrt{\frac{(x_1 - M)^2 + ... + (xn - M)^2}{N} }$

Because M does not change, if we add or subtract numbers to some of the values, the standard deviation will change (Because all the terms are squared, so the added and subtracted sevens don't cancel like in the previous cases)

Then the only value that does not have the same value in both the original and new data sets is the standard deviation.

6 0

3 years ago