Question 1058185
"I am a 4-digit odd number where the sum of my digits Is 22. 
<pre>
a = first digit
b = second digit
c = third digit
d = fourth (last) digit

a + b + c + d = 22 and d is odd</pre>the difference between my first digit and my last digit 
is equal to my third digit. <pre>a - d = c</pre>my second digit is twice my third digit.<pre>b = 2c</pre>My first digit is the domain value of f(x)=9x+3 if 
its corresponding range value is 66."<pre>
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=3</pre>What's my number?<pre>7843

Edwin</pre>