The answer would be: -0.75 I distributed the 0.9 to the .5 (I converted the fraction to a decimal) and the 2, afterwards I kept the parenthesis and subtracted the 0.45 with the positive 1.8 and I got -1.35. Then I added -1.35 to 0.6 and that's how I got -0.75 to be the solution.
I am probably wrong, but you could try doing PEMDAS after distributing the 0.9 to the .5 and 2. :)