SOLUTION: a number of two digit is such that four time the unit digit is 5 greather than thrice the ten digit when the digit are reversed, the number is increased by 9. find the number.

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Question 536367: a number of two digit is such that four time the unit digit is 5 greather than thrice the ten digit when the digit are reversed, the number is increased by 9. find the number.
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
Let xy be the number x in ten's place and y in units place
4y=3x+5
4y-3x=5................(1)
10y+x= 10x+y+9
9y-9x=9
/9
y-x=1...................(2)
-3 x + 4 y = 5 .............1
-1 x + 1 y = 1 .............2
Eliminate y
multiply (1)by -1
Multiply (2) by 4
3 x -4 y = -5
-4 x + 4 y = 4
Add the two equations
-1 x = -1
/ -1
x = 1
plug value of x in (1)
-3 x + 4 y = 5
-3 + 4 y = 5
4 y = 5 + 3
4 y = 8
y = 2
The number is 12
m.ananth@hotmail.ca