leniar equations in 2 variables
Asked by akshatverma | 9th Aug, 2009, 05:52: PM
let the ten's digit be x and the unit's digit be y.
so the number is 10x+y
acc to question,
10x+y=7(x+y)...(i)
and
10x+y=3xy-12..(ii)
from (i) we get,
3x=6y
i.e.
x=2y...(iii)
substituting this value of x in (ii) we get,
solving this quadratic, we get,
y=-1/2
or y=4
a digit can't be a fraction so y can't be -1/2
so y must be equal to 4.
so x=2y gives
x=8
so the reqd num is 84.
Answered by | 9th Aug, 2009, 08:02: PM
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