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3 years ago

-5(x - 1) = 2x - 7x + 5

Mathematics

2 answers:

prisoha [69]3 years ago

8 0

So let's rewrite the question again.

-5(x - 1) = 2x - 7x + 5

So we will solve from left to right.

-5(x-1) <- In here, we cannot add a variable to a whole number. So, we simply multiply -5 by x and -1.

-5(x - 1) = -5x+5

2x - 7x + 5 <- Here, we can subtract 2x-7x. They are both variables. But, we cannot add 5 to a variable.

2x - 7x + 5 = -5x+5

Now, here is the equation that we have so far.

-5x+5 = -5x+5

+5x +5x

----------------------

5=5

-5 -5

0=0

So in here, we can have anything. 1, 2, 3, 4, 5, 6, 100, anything. So, the answer is:

All Real Numbers

sergey [27]3 years ago

7 0

Answer:

This is true! 1x=1

Step-by-step explanation:

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Please dont ignore, Need help!!! Use the law of sines/cosines to find..

Ket [755]

Answer:

16. Angle C is approximately 13.0 degrees.

17. The length of segment BC is approximately 45.0.

18. Angle B is approximately 26.0 degrees.

15. The length of segment DF "e" is approximately 12.9.

Step-by-step explanation:

By the law of sine, the sine of interior angles of a triangle are proportional to the length of the side opposite to that angle.

For triangle ABC:

$\sin{A} = \sin{103\textdegree{}}$ ,
The opposite side of angle A $a = BC = 26$ ,
The angle C is to be found, and
The length of the side opposite to angle C $c = AB = 6$ .

$\displaystyle \frac{\sin{C}}{\sin{A}} = \frac{c}{a}$ .

$\displaystyle \sin{C} = \frac{c}{a}\cdot \sin{A} = \frac{6}{26}\times \sin{103\textdegree}$ .

$\displaystyle C = \sin^{-1}{(\sin{C}}) = \sin^{-1}{\left(\frac{c}{a}\cdot \sin{A}\right)} = \sin^{-1}{\left(\frac{6}{26}\times \sin{103\textdegree}}\right)} = 13.0\textdegree{}$ .

Note that the inverse sine function here $\sin^{-1}()$ is also known as arcsin.

By the law of cosine,

$c^{2} = a^{2} + b^{2} - 2\;a\cdot b\cdot \cos{C}$ ,

where

$a$ , $b$ , and $c$ are the lengths of sides of triangle ABC, and
$\cos{C}$ is the cosine of angle C.

For triangle ABC:

$b = 21$ ,
$c = 30$ ,
The length of $a$ (segment BC) is to be found, and
The cosine of angle A is $\cos{123\textdegree}$ .

Therefore, replace C in the equation with A, and the law of cosine will become:

$a^{2} = b^{2} + c^{2} - 2\;b\cdot c\cdot \cos{A}$ .

$\displaystyle \begin{aligned}a &= \sqrt{b^{2} + c^{2} - 2\;b\cdot c\cdot \cos{A}}\\&=\sqrt{21^{2} + 30^{2} - 2\times 21\times 30 \times \cos{123\textdegree}}\\&=45.0 \end{aligned}$ .

For triangle ABC:

$a = 14$ ,
$b = 9$ ,
$c = 6$ , and
Angle B is to be found.

Start by finding the cosine of angle B. Apply the law of cosine.

$b^{2} = a^{2} + c^{2} - 2\;a\cdot c\cdot \cos{B}$ .

$\displaystyle \cos{B} = \frac{a^{2} + c^{2} - b^{2}}{2\;a\cdot c}$ .

$\displaystyle B = \cos^{-1}{\left(\frac{a^{2} + c^{2} - b^{2}}{2\;a\cdot c}\right)} = \cos^{-1}{\left(\frac{14^{2} + 6^{2} - 9^{2}}{2\times 14\times 6}\right)} = 26.0\textdegree$ .

For triangle DEF:

The length of segment DF is to be found,
The length of segment EF is 9,
The sine of angle E is $\sin{64\textdegree}}$ , and
The sine of angle D is $\sin{39\textdegree}$ .

Apply the law of sine:

$\displaystyle \frac{DF}{EF} = \frac{\sin{E}}{\sin{D}}$

$\displaystyle DF = \frac{\sin{E}}{\sin{D}}\cdot EF = \frac{\sin{64\textdegree}}{39\textdegree} \times 9 = 12.9$ .

7 0

3 years ago

Can someone help me with this? its solving systems by substitution

yKpoI14uk [10]

Answer: x = 1 and y = 2

Given:
y = -3x + 5
5x - 4y = -3

Since we are given y, let’s sub it in the second equation.

5x - 4(-3x + 5) = -3
5x + 12x - 20 = -3
17x = 17
x = 1

After finding x, we can now find y.

5(1) - 4y = -3
-4y = -8
y = 2

Checking:

y = -3x + 5
2 = -3(1) + 5
2 = 2

5x - 4y = -3
5(1) - 4(2) = -3
-3 = -3

8 0

3 years ago

Please help with this!!! 25 points and i'll mark you brainliest!!! Show how you got answer!!!

HACTEHA [7]

Answer:

17.9°

Step-by-step explanation:

From trigonometry:

Opposite = 14

Adjacent = x

theta = 38°

hence;

tan theta = opposite/ adjacent

tan38° = 14/x

x = 14/tan38°

x = 17.9°

6 0

3 years ago

Mr. Pham wrote the equation below on the board. 18 - 7x = -20.5 What is the value of x?

slavikrds [6]

Use the arithmetic operations to get the variable x on one side of the equation and everything else on the opposite side.

If something is being is being done to a variable, we undo that operation by using the inverse of that operation.

For example, if 10 is being added to x, we use the inverse of addition or subtraction.

18 - 7x = -20.5

We variable x is being multiplied by 7 and is subtracting 18. We need to undo all those operations.

18 - 7x = -20.5
-7x = -38.5

Now the variable is only being multiplied by -7. Reverse the operation.

-7x = -38.5
x = 5.5

So, x is equal to 5.5.

7 0

3 years ago

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A total of 279 tickets were sold for the school play. they were either adult or student tickets. the number of student tickets s

Mice21 [21]

A + s = 279
s = 2a

a + 2a = 279
3a = 279
a = 279/3
a = 93 <=== adult

s = 2a
s = 2(93)
s = 186 ....students

6 0

4 years ago

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