Answer:
45
Step-by-step explanation:
You want the number described by, "twice the sum of a number and 9 is equal to three times the difference of the number and 9."
Setup
Let x represent the number. Then "twice the sum of the number and 9" is ...
2(x +9)
and "three times the difference of the number and 9" is ...
3(x -9)
These are equal, so we have ...
2(x +9) = 3(x -9)
Solution
Eliminating parentheses gives ...
2x +18 = 3x -27
45 = x . . . . . . . . . . . add 27-2x
The number is 45.
