Answer:
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Step-by-step explanation:
☆ (x₁, y₁) is the 1st coordinate and (x₂, y₂) is the 2nd coordinate.
Slope of the line
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Notice that the 2 points have the same x-coordinate of -1, which means that the line is a vertical line. Vertical lines have an undefined slope.
The speed of the stream: v s = 1 mph
v - David`s speed in still water
( v - 1 ) t 1 = 3
( v + 1 ) t 2 = 3
t 1 + t 2 = 4
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t 2 = 4 - t 1
3 = ( v - 1 ) * t 1
3 = ( v + 1 ) * ( 4 - t 1 )
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3 = v t 1 - t 1
+
3 = 4 v - v t 1 + 4 - t 1
------------------------------
6 = 4 v + 4 - 2 t 1
2 = 4 v - 2 t 1
2 t 1 = 4 v - 2 / : 2 ( divide both sides of equation by 2)
t 1 = 2 v - 1
t 2 = 5 - 2 v
------------------
3 = ( v - 1 ) * ( 2 v - 1 )
3 = 2 v² - 3 v + 1
2 v² - 3 v - 2 = 0
v 1/2 = 3+/- √(9 + 16 ) / 4 = (3 + 5)/4 = 8/4 = 2 ( other solution is negative )
Answer: David`s speed in still water is 2 miles per hour.
Answer:
x = 9
Step-by-step explanation:
The question is shown in the attached figure.
We can see that, (8x + 5)° and (13x – 14)° forms a linear pair. It would mean that,
(8x + 5)° + (13x – 14)° = 180°
21x-9 = 180°
21x = 180° + 9
21x = 189
x = 9
Hence, the value of x is 9.
The total surface area of the given pyramid is:
A = 39ft²
<h3>
How to get the surface area of the given figure?</h3>
The total surface area will be equal to the sum of the areas of the square and the 4 triangles.
Remember that for a square of side length S, the area is:
A = S².
In this case, S = 3ft, then:
A = (3ft)² = 9ft².
Now, the area of a triangle of base B and height H is:
A = B*H/2.
Here we can see that the triangles have a base of 3ft (the sides of the square) and a height of 5ft, then the area of each triangle is:
A = (3ft)*(5ft)/2 = 7.5 ft²
Then the total area of the figure is:
A = 4*(7.5 ft²) + 9ft² = 39ft²
If you want to learn more about pyramids:
brainly.com/question/10042135
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