SOLUTION: A two digit number is seven times the sum of its digit and is also equal to 12 less than 3 times the product of its digit. find the number. Find the number.

Question 522065: A two digit number is seven times the sum of its digit and is also equal to 12 less than 3 times the product of its digit. find the number. Find the number.
Answer by mananth(16946) (Show Source): You can put this solution on YOUR website!
let the number be xy
x in ten's place
10x+y = 7(x+y)
10x+y = 7x+7y
3x-6y=0
3x=6y
x=2y-------1
10x+y =3xy -12
substitute x=2y
10x-3xy+y=-12
10*2y-3*2y*y+y=-12
20y-6y^2+y=-12
6y^2-21y-12=0
6y^2-24y+3y-12=0
6y(y-4)+3(y-4)=0
(y-4)(6y+3)=0
y=4 .
x=2y
x=8
the number is 84
m.ananth@hotmail.ca
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