Question 698970
x= 	number of student tickets							
y=	number of adult tickets							
Total  sold								
4	x	+	6	y	=	180	.............1	
								
1	x	+	1	y	=	40	.............2	
Eliminate	y							
multiply (1)by		1						
Multiply (2) by		-6						
4	x		6	y	=	180		
-6	x		-6	y	=	-240		
Add the two equations								
-2	x				=	-60		
/	-2							
x	=	30						
plug value of			x	in (1)				
4	x	+	6	y	=	180		
120		+	6	y	=	180		
			6	y	=	180		-120
			6	y	=	60		
				y	=	10		
x=	30		number of student tickets					
y=	10		number of adult tickets		


Substitution

1	x	+	1	y	=	40	.............1				
1	y	=	40	+	-1	x					
/	1	=									
	y	=	40	+	-1	x					
4	x	+	6	y	=	180		.....................2			
Substitute y in		(2)									
4	x	+	6	(	40	+	-1	x	)	=	180
4	x	+	240	+	-6	x	=	180			
4	x		-6	x	=	-60					
-2	x	=	-60								
/	-2										
x=	30      										
Plug the value of x in (1)											
1	x	+	1	y	=	40					
1	*	30      	+	1	y	=	40				
30      	+	1	y	=	40						
1	y	=	10      								
/	1										
y=	10      

x=	30		number of student tickets					
y=	10		number of adult tickets		

Graph

1	x	+	1	y	=	40	.............1	
4	x		6	y	=	180	.............2	
Find the x & y intercept points by plugging x=0,y=0 in both equations.								
equation I								
when x=	0	y=	40	,(	0	,	40	)
when y =	0	x=	40	,(	40	,	0	)
Equation 2								
when x=	0	y=	30	(	0	,	30	)
when y =	0	x=	45	(	45	,	0	)
								
{{{drawing(500,500,-10,50,-10,20,grid(0.1),circle(0,40,0.3),circle(40,0,0.3),circle(0,30,0.3),circle(45,0,0.3),graph(500,500,-10,50,-10,20,y=40-x,y=-(2/3)x+30))}}}								
								
You will observe that the point of intersection is						30,10