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2 years ago

WILL GIVE BRAINLIEST. If x+y=3 and 3x+5y=13, then x-y is equal to?

Mathematics

1 answer:

Alex17521 [72]2 years ago

6 0

Answer:

(1,2)

y=2

x=1

Step-by-step explanation:

x+y=3

3x+5y=13

solve the equation

x=3-y

3x+5y=13

substitute the value of x into an equation

3(3-y)+5y=13

distribute

9-3y+5y=13

add -3y to 5y

9+2y=13

subtract 9 from both sides

2y=4

divide both sides by 2

y=2

substitute the value of y into an equation

x=3-2

subtract 3 to 2

x=1

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(1,2)

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Need help on these trig homework

allochka39001 [22]

8. The length of the support is 7. 9 m

9. The length of the conveyer is 12m

3. a = 59m

A = 44°

B = 52°

4. c = 88. 6 mm

b = 49. 1 m

B = 34°

<h3>How to solve the trigonometry</h3>

8. We have the angle to be 20 degrees

Opposite side = x

hypotenuse = 23m

Using the sine ratio

sin θ = opposite/ hypotenuse

$sin 20 = \frac{x}{23}$

Cross multiply

$sin 20$ × $23 = x$

$x = 0. 3420$ × $23$

x = 7. 9 m

The length of the support is 7. 9 m

9. The angle of elevation is 37. 3 degrees

Hypotenuse = 19 . 0m

Opposite = x

Using the sine ratio

sin θ = opposite/ hypotenuse

$sin 37. 3 = \frac{x}{19}$

cross multiply

$x = 0. 6059$ × $19$

x = 11.5

x = 12 m in 2 significant figures

The length of the conveyer is 12m

3. To determine the sides and angles, we use the sine rule;

$\frac{a}{sin A} = \frac{b}{sin B} = \frac{c}{sin C}$

For side a, we use the Pythagorean theorem

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

$85^2 = a^2 + 67^2$

$a = \sqrt{89^2-67^2}$

$a = \sqrt{3432}$

a = 58. 58, a = 59m

To find angle A and B, use the sine rule

$\frac{59}{sin A } = \frac{85}{sin 90}$

cross multiply

$sin A$ × $85$ = $sin 90$ × $59$

make sin A subject of formula

$sin A = \frac{59}{85}$

$sin A = 0. 6941$

A = $sin^-^1(0. 6941)$

A = 44°

$\frac{67}{sin B} = \frac{85}{sin 90}$

cross multiply

$sin B$ × $85$ = $sin 90$ × $67$

make sin b subject of formula

$sin B = \frac{67}{85}$

$sin B = 0. 7882$

B = $sin^-^1( 0. 7882)$

B = 52°

4. To find the sides, we use the sine rule;

$\frac{74. 0}{sin 56. 6} = \frac{c}{sin 90}$

Cross multiply

$sin 56. 6$ × $c = sin 90$ × $74$

make 'c' subject of formula

$c = \frac{74}{0. 8348}$

c = 88. 6 mm

To find length b, we use the Pythagorean theorem

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

$b^2 = c^2 - a^2$

$b^2 = 88. 8^2 - 74^2$

$b = \sqrt{7885. 44 - 5476}\\\\ b = \sqrt{2409. 44}$

b = 49. 1 m

$\frac{74. 0}{sin 56. 6} = \frac{49. 1}{sin B}$

cross multiply

$sin B = \frac{40. 99}{74. 0}$

B = $sin^-^1(0. 5539)$

B = 34°

Learn more about trigonometric identity here:

brainly.com/question/7331447

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3 0

1 year ago

What percent of 70 is 10.5? (write your answer as a percent) A) 10.5% Eliminate B) 11.0% C) 12.5% D) 15.0%

Roman55 [17]

Answer:

Option D) 15%

Step-by-step explanation: 10.5/70= .15

.15x100=15

It would be easier to think it through if instead for 70 we took the number 100. Lets reword it and say what percent of 100 is 38? This would be easy to answer it would be 38% But how you check it is, you take 38 and divide by the total (100) which is .38 then multiply by 100 you will get 38% Same with your equation take the 10.5 and divide by the total amount which is 70 you will get .15 then multiply by 100. the answer will be 15%

7 0

3 years ago

Read 2 more answers

Find the total volume of the composite figure below. Round to the nearest thousandth.

cestrela7 [59]

Answer:

The volume of the composite figure is approximately 3567.198 cubic feet.

Step-by-step explanation:

The composite figure consists in the combination of a right cone and a cuboid. The volume of the composite ( $V$ ), in cubic feet, figure can be determined by this expression: