Answer:
k=4
Step-by-step explanation:
5-7k=-4(k+1)-3
Distribute
5-7k=-4k-4-3
Combine like terms
5-7k=-4k-7
Add 7k to each side
5-7k +7k = -4k+7k-7
5 = 3k-7
Add 7 to each side
5+7 = 3k-7+7
12 = 3k
Divide by 3
12/3 = 3k/3
4=k
 
        
                    
             
        
        
        
Given :
A sailor is 30 m above the water in the crow's nest on a sailboat. 
The sailor encounters an orca surface at an angle of depression of 15 degrees.
The crows nest is 20 m horizontally from the bow (front) of the boat. 
To Find :
 How far in front of the boat is the orca.
Solution :
Let, distance of boat front from the crow's nest is x.
So,
 
Hence, this is the required solution.
 
        
             
        
        
        
2t+3n=9                                                   2(2)+3n=9
+5t-3n=5 (the 3n cancel out)                   4+3n=9
7t=14                                                       3n=5
t=2                                                           n=5/3 or 1.67
        
             
        
        
        
Answer: 10
Step-by-step explanation:
In a right angle triangle 
Hypothenus ^2= opposite ^2+ adjacent ^2
According to a diagram below
Hypothenus =15
Opposite =?
Adjacent =11
Substitute for the values
15^2=11^2+opp^2
Opp^2=15^2-11^2
0pp^2= 225-121
Opp2=104
Opp= square root of 104
Opp= 10.2
Opp= ~10