To solve for "u", you need to isolate/get the variable "u" by itself in the equation:
1.5u + 8.0 = 3.5 Subtract 8.0 on both sides
1.5u + 8.0 - 8.0 = 3.5 - 8.0
1.5u = -4.5 Divide 1.5 on both sides to get "u" by itself
[tex]\frac{1.5u}{1.5} =\frac{-4.5}{1.5}[/tex]
u = -3
PROOF
1.5u + 8.0 = 3.5 Plug in -3 for "u"
1.5(-3) + 8.0 = 3.5
-4.5 + 8.0 = 3.5
3.5 = 3.5
