solve

0.07-0.003x+0.2=1.02

-.003x = 1.02 - 0.07 - 0.2
-.003x = 0.75
x = 1.75/-.003
x = -250

personally I would have multiplied each term by 1000 to get rid of all those nasty decimals

70 - 3x + 200 = 1020
-3x = 1020 - 70 - 200
-3x = 750
x = -250