It helps to imagine the variable a sort of as a unit. Like with 5 minus 12 lemons, it has no bearings on the addition/subtraction here.
Factor out a and subtract.
the answer you're looking for, rounded to the nearest thousandth, is 0.006 and we get that answer because we must round 0.0057 to the nearest thousandth, meaning that we must look at the seven, and realize that the seven tells us that the 5 is supposed to be a 6 because we are rounding to the nearest thousandth. So the answer is 0.006 I hope that this helps!
12xy i think lol :) hope that helps a bit
I really don't know how toowrk it out on paper, I'm afraid. I just looked at it, and somehow knew that the answers are 7 and 9.