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77julia77 [94]
2 years ago
9

Solve the systems using substitution. − 2x − 5y = − 5 x = 5y − 20

Mathematics
1 answer:
Law Incorporation [45]2 years ago
7 0
-2(5y-20) - 5y = -5
-10y + 40 - 5y = -5
-15y + 40 = -5
-15y = -45, y = 3
x = 5(3) - 20
x = 15 - 20, x = -5
Solution: x = -5, y = 3... or (-5,3)
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One of the tallest buildings in a country is topped by a high antenna. The angle of elevation from the position of a surveyor on
irina1246 [14]

Answer:

a. distance of the surveyor to the base of the building = 2051.90 ft

b. height of the building = 1384 ft

c. Angle of elevation from the surveyor to the top of the antenna = 38.31°

d. Height of antenna  =  237.08 ft

Step-by-step explanation:

​The picture above is a illustration of the described event.

a = the height of the flag

b = the height of the building

c = distance of the surveyor from the base of the building

the angle of elevation from the position of the surveyor on the ground to the top of the building = 34°  

distance from her position to the top of the building  = 2475 ft

distance from her position to the top of the flag  = 2615 ft

​(a) How far away from the base of the building is the surveyor​ located?​

using the SOHCAHTOA principle

cos 34° = c/2475

c =  0.8290375726  × 2475

c = 2051.8679921

c = 2051.90 ft

(b) How tall is the​ building

The height of the building = b

sin 34° = opposite /hypotenuse

0.5591929035 = b/2475

b =  0.5591929035  × 2475

b =  1384.0024361

b =  1384.00 ft

​(c) What is the angle of elevation from the surveyor to the top of the​ antenna?

let the angle = ∅

cos ∅ = adjacent/hypotenuse

cos ∅ = 2051.90/2615

cos ∅ =  0.784665392

∅ = cos-1  0.784665392

∅ =   38.310258303

∅ =  38.31°

​(d) How tall is the​ antenna?

height of the antenna = a

sin 38.31° = opposite/hypotenuse

sin 38.31° = (a + b)/2615

sin 38.31° × 2615 = (a + b)

(a + b) =  0.6199159917  × 2615

(a + b) =  1621.0803182

(a + b) = 1621. 08 ft

Height of antenna = 1621. 08 - 1384.00  =  237.08031822 ft

Height of antenna  =  237.08 ft

8 0
3 years ago
What is the value of 30-2(7+2)-1
Firdavs [7]

Answer: 11

Step-by-step explanation:

30 - 2(7+2)- 1        Distribute or  solve parentheses

30 - 14 -4 - 1  

30 - 19 = 11  

6 0
3 years ago
What does it mean when two things are opposites?
svetoff [14.1K]

Answer:

Step-by-step explanation:

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6 0
2 years ago
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The sum of five times a number and -6 is -2
k0ka [10]
5n + (-6) = -2
add 6 to -2
5n = -2 + 6
5n = 4
divide both sides by 5
n = 4/5
4 0
3 years ago
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I apologized that you have not been helped yet, But the answer is (0,-5). Again, I am so sorry that you were not helped properly :)
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