Answers

2014-06-14T21:06:03+08:00
Let z=Juan's age in 1989

z=10+x+y

x-y-6=0
x-y=6
To find z
-z=-10-x-y
-z=-10-6
-z=-16
 z=16

Substitute
z=10+x+y
16=10+x+y
6=x+y

To get x and y
x+y=6
x-y=6
2x=12
x=6
y=0

His age in 1989 is 16 therefore his age in 1980 is 7
*Anyone can correct my solution in case of errors. But in the meantime, here's your answer:)



1 2 1
Nb77? Can i ask something? why do we have 10 in the first equation ?
1+9=10
Ahhh Okay Thanks
Who has another answer ?
oh wait im sorry please change my answer from 1980 to 1990, so the final answer is 17. im really sorry haha