0.2x + 0.9 = 0.3 - 0.1x
0.2x+0.9 = 0.3-0.1x
0.2x+0.1x = 0.3-0.9
0.3x = -0.6
x = -0.6/0.3
x = -0.2
First get the variables onto one side. Add 0.1x to both sides and subtract 0.9 to both side. You should get 0.3x=-0.6. Divdie 0.3 to both side and x=2. Hope that helps.
