quadratic, not linear
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2 yrs ago::::: son : x , father 3x^2
3 yrs hence: son x+5, father 4(x+5)
4(x+5) - 3x^2 = 5
open out & collect terms
3x^2 - 4x - 15 = 0
factorise
(3x+5)(x-3) = 0
take +ve solution
x = 3
2 yrs ago, son was 3, father was 27
present ages : son = 5 yrs, father = 29 yrs
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IF THE ABOVE ANS IS WRONG,
IT'S BECAUSE OF AMBIGUOUS USE OF "HENCE"
ANOTHER INTERPRETATION BELOW
2 yrs ago::::: son : x , father 3x^2
3 yrs hence: son x+1, father 4(x+1)
4(x+1) - 3x^2 = 3
open out & collect terms
3x^2 - 4x - 7 = 0
factorise
(3x-7)(x+1) = 0
take +ve solution
x = 7/3
2 yrs ago, son was 2 1/3, father was 49
present ages : son = 4 1/3 yrs, father = 51 yrs
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