Math problems!!! 11th grade Algebra II HELP!!!?
The sum of the digits of a two-digit number is 14. The Difference between the ten's digit and the unit's digit is 2 find the number [Let t=ten's digit and u=unit's digit]
The sum of the digits of a two-digit number is 14. The Difference between the ten's digit and the unit's digit is 2 find the number [Let t=ten's digit and u=unit's digit]
Comments
Add the two equations to eliminate the u:
t + u = 14
+(t - u = 2)
---------------
2t = 16
Divide both sides by 2:
t = 8
Substitute 8 for t in equation 1:
8 + u = 14
Subtract 8 from both sides:
u = 6
The number is 86.
Use a simple substitution:
t - u = 2 so t = 2 + u and
t + u = 14 so
2 + u + u = 14
2u = 12 and u = 6 and t = 8 and the number is 86
t + u = 14
t - u = 2 OR -2; you don't specify which is larger
rearrange t + u = 14 to t = 14 - u
insert into the second equation to get
14 - u - u = 2 or -2
14 - 2u = 2 or -2
12 = 2u or 16 = 2u
u = 6 or 8
t = 8 or 6
So it is either 68 or 86
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t + u = 14
-
t - u = 2
-----------------
2u = 12
u = 6
t -6 = 2
t = 8
t=8, u=6
86