To solve this equation, we first need to simplify the expression in the parentheses:

20 + 45 - 0.92x = 65 - 0.92x

Now we can substitute this into the original equation:

(65 - 0.92x) - 3.2 = 51
65 - 0.92x - 3.2 = 51
61.8 - 0.92x = 51

Now we can isolate the variable by first adding 0.92x to both sides:

61.8 = 0.92x + 51

Next, subtract 51 from both sides:

10.8 = 0.92x

Finally, divide by 0.92 to solve for x:

x = 10.8 / 0.92
x = 11.74

So the solution to the equation is x = 11.74.