Answer:
 x = 3 1/2
Explanation:
You could simplify the given equation first, then solve the resulting 2-step linear equation. It might work better to undo the operations done to the variable.
Solution
 (5 1/6 -x)(2.7) -5 3/4 = -1 1/4 . . . . . given
 (5 1/6) -x)(2.7) = 4 1/2 . . . . . . . add 5 3/4 to both sides
 (5 1/6 -x) = 4.5/2.7 = 5/3 . . . divide by 2.7
 31/6 -10/6 = x . . . . . . . . . . add x-5/3, use common denominators
 21/6 = x = 7/2
 x = 3 1/2