Question

Find the variable
0.3a+(0.2a-0.5)+0.2(a+2)=1.3

Answer 1

The variable, I assume, is a.
If you want to know the value of a, use algebra to get
0.5a -0.5 +0.2a +0.4 = 1.3
0.7 a = 1.4
Divide both sides by 0.7 for the final answer.

Answer 2

a=2