Question 715609
husband --------- x
wife = y

{{{x/y=4/3)}}}

3x-4y=0...................(1)


after 4  years

(x+4)/(y+4) =9/7

7(x+4)=9(y+4)

7x+28=9y+36

7x-9y=8..............(2

x= 	husband's age							
y=	wife's age							
 								
3	x		-4	y	=	0	.............1	
Total value								
7	x		-9	y	=	8	.............2	
Eliminate	y							
multiply (1)by		-9						
Multiply (2) by		4						
-27	x		36	y	=	0		
28	x		-36	y	=	32		
Add the two equations								
1	x				=	32		
/	1							
x	=	32      						
plug value of			x	in (1)				
3	x		-4	y	=	0		
96			-4	y	=	0		
			-4	y	=	0		-96
			-4	y	=	-96		
				y	=	24      		
x=	32      		husband's age					
y=	24      		wife's age					
)


let a be the years ago they married

(x-a)/(y-a) =5/3

(32-a)/(24-a) =5/3

3(32-a)=5(24-a)

96-3a=120-5a

2a=24
a=12

They got married 12 years ago