Remember you can do anything to do anything to an equation as long as you do it to both sides
n-8<10
add 8 to both sides
n-8+8<10+8
n+0<18
n<18
<h2>
Hello!</h2>
The answer is:
The correct option is:
D. 40 feet.
<h2>
Why?</h2>
To solve the problem and calculate the width of the river, we need to assume that the distance from A to B and the angle formed between that distance and the distance from A to the other point (C) is equal to 90°, meaning that we are working with a right triangle, also, we need to use the given angle which is equal to 34°. So, to solve the problem we can use the following trigonometric relation:

Where,
alpha is the given angle, 34°
Adjacent is the distance from A to B, which is equal to 60 feet.
Opposite is the distance from A to C which is also equal to the width of the river.
So, substituting and calculating we have:


Hence, we have that the correct option is:
D. 40 feet.
Have a nice day!
(1,2)(3,4)
slope = (4 - 2) / (3 - 1) = 2/2 = 1
y = mx + b
slope(m) = 1
use either of ur sets of points...(1,2)....x = 1 and y = 2
now we sub and find b, the y int
2 = 1(1) + b
2 = 1 + b
2 - 1 = b
1 = b
so ur equation is : y = x + 1