Answer
All Real Numbers. (Any real number will satisfy the equation)
Work Step by Step
Solve : 9x - 10 = 5x + 2(2x-5)
9x - 10 = 5x + 4x - 10
9x - 10 = 9x - 10
LHS = RHS always , ie. , for any real number this equation is true
Hence all real numbers satisfy it.