Use the equation 2,401 = 76 – 2x. What power of 7 is 2,401?

Comment
I'm going to take a guess at this and say what you meant is  2401 = 7^(6 - 2x)

Step One
Find out the power of 7 that will equal 2401. 
You could do it like this.
7^y = 2401 and just guess at some values.

y      7^y
1      7
2      49
3      7 * 7 * 7 = 343
4      7 * 7 * 7 * 7 = 2401  So the answer is 4

7^4 = 2401

Step 2 
Equate the powers.
2401 = 7^(6 - 2x)
7^4 = 7^ (6 - 2x)
4 = 6 - 2x  Subtract 6 from both sides.
4 - 6 = - 2x 
-2 = - 2x divide by - 2
-2/-2 = x
x = 1 <<<<<<<<<<<<<answer