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2 years ago

Find the value of x for the function y=-2(x+7) if y has a value of 20

Mathematics

2 answers:

Ahat [919]2 years ago

8 0

Answer:

x=-17

Step-by-step explanation:

-2(x+7)=20

distibute the -2

-2x-14=20

add 14 to both sides

-2x=34

divide by -2

x=-17

Wewaii [24]2 years ago

4 0

Answer:

x=3

Step-by-step explanation:

put the value of y=20 in equation

20=2(x+7)

20=2x+14

20-14=2x

6=2x

6/2=x

x=3

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For positive acute angles AA and B,B, it is known that \tan A=\frac{28}{45}tanA= 45 28 and \cos B=\frac{3}{5}.CosB= 5 3 . Fi

MrRa [10]

Answer:

$\cos(A + B) = \frac{23}{265}$

Step-by-step explanation:

Given

$\tan A=\frac{28}{45}$

$\cos B=\frac{3}{5}$

Required

$\cos(A+B)$

In trigonometry:

$\cos(A+B) = \cos\ A\ cosB - sinA\ sinB$

We need to solve for cosA, sinA and sinB

Given that:

$\tan A=\frac{28}{45}$ and the tangent of an angle is a ratio of the opposite side (x) to the adjacent side (y),

So, we have:

$x =28$ and $y = 45$

For this angle A, we need t calculate its hypotenuse (z).

Using Pythagoras,

$z^2 = x^2 + y^2$

$z = \sqrt{x^2 + y^2$

$z = \sqrt{28^2 + 45^2$

$z = \sqrt{2809$

$z = 53$

From here, we can calculate sin and cos A

$\sin A= \frac{opposite}{hypotenuse}$ and $\cos A= \frac{adjacent}{hypotenuse}$

$\sin A= \frac{x}{z}$

$\sin A= \frac{28}{53}$

$\cos A= \frac{y}{z}$

$\cos A= \frac{45}{53}$

To angle B.

Give that

$\cos B=\frac{3}{5}$ and the cosine of an angle is a ratio of the adjacent side (a) to the hypotenuse side (c),

So, we have:

$a = 3$ and $b = 5$

For this angle B, we need to calculate its opposite (b).

Using Pythagoras,

$c^2 = a^2 + b^2$

$5^2 = 3^2 + b^2$

$25 = 9 + b^2$

Collect like terms

$b^2 = 25 - 9$

$b^2 = 16$

$b = \sqrt{16$

$b = 4$

From here, we can calculate sin B

$\sin B= \frac{opposite}{hypotenuse}$

$\sin B = \frac{b}{c}$

$\sin B = \frac{4}{5}$

Recall that:

$\cos(A+B) = \cos\ A\ cosB - sinA\ sinB$

and

$\cos B=\frac{3}{5}$ $\sin B = \frac{4}{5}$ $\sin A= \frac{28}{53}$ $\cos A= \frac{45}{53}$

$\cos(A + B) = \frac{45}{53} * \frac{3}{5} - \frac{28}{53} * \frac{4}{5}$

$\cos(A + B) = \frac{135}{265} - \frac{112}{265}$

$\cos(A + B) = \frac{135-112}{265}$

$\cos(A + B) = \frac{23}{265}$

7 0

2 years ago

What is equivalent to 2^5

Akimi4 [234]

Answer:

Step-by-step explanation:

2⁵ = 2*2*2*2*2

= 32

3 0

2 years ago

Don wants to keep his favorite pine tree from being uprooted by heavy winds. He plans to tie 3 sections of rope to a band on the

iragen [17]

Answer:64 feet i think

Step-by-step explanation:

3 0

3 years ago

Read 2 more answers

Which of the following expresses the possible number of positive real solutions for the polynomial equation shown below?

sesenic [268]

Answer: D. Two or zero

Step-by-step explanation: x=-7/6+-1/6√385

There isn't an exact place you could really solve this number, regardless of the way you break it down

5 0

3 years ago

So I really don't understand what I'm doing....I would be glad if you helped

SSSSS [86.1K]

We are supposed to assume FC and AD is straight line
let's find all the angles

you already see the right angle is 90 degrees, you got that right
striaght line is 180 degrees

90+46+EF=180
136+EF=180
minus 136 both sides
EF=44
now we got another straight line
you did get that A F=46 because it is oposite

notice: AB=BC because same angle designition
so now we use
180+46+2AB=360
2AB=134
divide 2
AB=67=BC
AC=134 degrees
CAE=134+46+44=224
ABD=180 since straight line

a. 90
b. 224
c.134
d. 180

8 0

3 years ago