Question 1176532
Carl and Dennis are brothers. The sum of their age is 29. 
c + d = 29
In 6 year time Carl will be the same age as Dennis was 3 years ago
c + 6 = d - 3
c - d = -3 - 6
c - d = -9
 how old is Carl and how old are both the brothers
use elimination with these two equations
c + d = 29
c - d = -9
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2c + 0 = 20
c = 20/2
c = 10 yrs is Carl's age
then, obviously, 19 is Dennis' age
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Check in the statement
"In 6 year time Carl will be the same age as Dennis was 3 years ago"
10 + 6 = 19 - 3