"I am a 4-digit odd number where the sum of my digits Is 22.
a = first digit
b = second digit
c = third digit
d = fourth (last) digit
a + b + c + d = 22 and d is odd
the difference between my first digit and my last digit
is equal to my third digit. a - d = c
my second digit is twice my third digit.b = 2c
My first digit is the domain value of f(x)=9x+3 if
its corresponding range value is 66."
We find the value of x for which f(x) = 66 by setting
f(x) = 66
9x+3 = 66
9x = 63
x = 7
So the domain value for the range value of 66 is 7
Therefore the first digit = a = 7
The information so far is:
(1) a + b + c + d = 22 and d is odd
(2) a - d = c
(3) b = 2c
(4) a = 7
Substituting 7 for a in (1) and (2)
(1) a + b + c + d = 22 and d is odd
7 + b + c + d = 22 and d is odd
(5) b + c + d = 15 and d is odd
(2) 7 - d = c
7 = c + d
(6) c + d = 7
Subtracting (6) from (5):
(5) b + c + d = 15 and d is odd
(6) c + d = 7
------------------------
b = 8
Substituting 8 for b in (3)
(3) b = 2c
8 = 2c
4 = c
Substituting 4 for c in (6)
(6) c + d = 7
4 + d = 7
d = 3 <-- yes, d is odd.
So now we have a=7, n=8, c=4, d=3What's my number?7843
Edwin