<PRE><B>Question 468234</B>
Boat speed		x   		
current speed 		2		
				
against current x-2	mph	
with current x+	2	mph	
				
Distance= 5	miles		
				
Time against + time with  = 6	hours

5	/(	x   	+	2	)	+	5	/(x	-	2	)	=	6				
																	
LCD =	(x	-	2	)	(	x   	+	2	)								
5	*(	x   	-	2	)	+	5	(x	+	2	)	=	6				
5	x   	-	10	+	5	x   	+	10		=	6	(	x ^2		-	4	)
10	x   	=	6	x ^2	-	24											
6	x ^2	-	-10	x   	-	24											
																	
Find the roots of the equation by quadratic formula			
a=	6	,	b=	-10	,	c=	-24		
b^2-4ac=	100	+	576					
b^2-4ac=676	
{{{	sqrt(	676	)=	26	}}}									
{{{x=(-b+-sqrt(b^2-4ac))/(2a)}}}																	
{{{x1=(-b+sqrt(b^2-4ac))/(2a)}}}																	
x1=(10+26)/12												
x1=3																
x2=(10-26)/12													
x2= 	-1.33																
Ignore negative value											
Speed of boat is 3 mph						

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