<PRE><B>Question 871931</B>
going	speed	x				
returning	speed	x	+	10		
						
	Distance = same		200	miles	1	
	original time – time with increased speed =					1
	t=d/t					
200	/	x	-	200	/	(	x	+	10	)	=	1				
LCD=	x	(	x	+	10	)										
multiply by LCD																
200	(	x	+	10	)	-	200	x	=	1	x	(	x	+	10	)
200	x	+	2000	-	200	x	=	1	X^2	+	10	x				
2000	=	1	X^2	+	10	x										
1	X^2		+	10	x	-	-2000	=	0							
Find roots of the quadratic equation																
a=	1		b=	10		c=	-2000									
																
x1=	(	-10	+	sqrt(		100	-	8000	))	/	2					
x1=(	-10	+	90	)/	2											
x1=	40															
																
x2=	(	-7	-	sqrt(		49	-	20	)	/	2					
x2=(	-10	-	90	)/	2											
x2=	-50															
ignore negative

going speed = 40 mph</PRE>