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3 years ago

Sin ( 90 + theta ) = cos theta prove^

1 answer:

5 0

We will use additional formula:
sin ( 90°+ theta ) = sin 90° * cos(theta) + cos 90° * sin(theta)=
= 1 * cos(theta) + 0 * sin(theta)= cos (theta) It is proved.

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I need to figure out how many solutions does the system of equations below have.

Aleonysh [2.5K]

Answer:

The system has one solution.

Step-by-step explanation:

To find the number of solutions of the system, we equal both equations for y.

If we have ax = b, in which both a and b are different of 0, we have one solution.

If both a and b are 0, we have infinite solutions.

If a is 0 and b is not, there are no solutions.

y=6/7x-8 and y=7/9x+10/9

$\frac{6x}{7} - 8 = \frac{7x}{9} + \frac{10}{9}$

$\frac{6x}{7} - \frac{7x}{9} = \frac{10}{9} + 8$

$\frac{54x - 49x}{63} = \frac{10}{9} + \frac{72}{9}$

$\frac{5x}{63} = \frac{82}{9}$

$45x = 63*82$

Both a and b are different of 0, so the system has one solution.

6 0

2 years ago

How to find the perimeter? And how to I do it

Veronika [31]

Answer:

multiply lenght x with

Step-by-step explanation:

3 0

3 years ago

Two customers went to a post office to buy postcards and large envelopes. Each postcard

astraxan [27]

The right answer is Option A.

Step-by-step explanation:

Let,

x be the postcards

y be the large envelops

According to given statement;

14x+5y=12 Eqn 1

10x+15y=24.80 Eqn 2

Multiplying Eqn 1 by 3;

$3(14x+5y=12)\\42x+15y=36\ \ \ Eqn \ 3$

Subtracting Eqn 2 from Eqn 3;

$(42x+15y)-(10x+15y)=36-24.80\\42x+15y-10x-15y=11.20\\32x=11.20\\$

Dividing both sides by 32

$\frac{32x}{32}=\frac{11.20}{32}\\x=0.35$

Putting x=0.35 in Eqn 1;

$14(0.35)+5y=12\\4.90+5y=12\\5y=12-4.90\\5y=7.10$

Dividing both sides by 5

$\frac{5y}{5}=\frac{7.10}{5}\\y=1.42$

Therefore, one large envelope costs $1.42

The right answer is Option A.

Keywords: linear equations, subtraction

Learn more about linear equations at:

#LearnwithBrainly

4 0

3 years ago

Translate into an algebraic expression and simplify if possible. I have a total of 10 gigabytes of data on my computer, xgigabyt

pogonyaev

Answer:

(20-3x)/2 GB

Explanation:

Total amount of data on my computer = 10GB

Total amount of data occupied by movies = x GB

If pictures take up half the amount of space that movies do, then;

Total amount of data occupied by pictures = 1/2 of space occupied by movies = 1/2 x

If the remaining are music, the amount of space occupied by music will be expressed as shown;

Total space -(space occupied by movies + space occupied by pictures)

= 10 - (x+1/2 x)

Total amount of data occupied by music = 10 - (x+1/2 x) GB

On simplification;

= 10 - (x+1/2 x)

= 10-{(2x+x)/2}

= 10 - {3x/2}

= (20-3x)/2 GB

Hence, amount of gigabytes of music stored on my computer is expressed as (20-3x)/2 GB.

4 0

3 years ago

What is the area of this figure? 49.5 in² 66.5 in² 84 in² 91 in²

Nookie1986 [14]

D 19 in2
find the area of a square, width times height
then find the area of the triangle, width times height divided by 2

6 0

3 years ago

Read 2 more answers