Question

5+9+(3,39r)=−2+5−6,61r
помогите ​

Answer 1

5+9+(3,39r)= -2+5-6,61r
9+3,39r= -2-6,61r
3,39r+6,61r= -2-9
10r = -11
r = -11/10
r = -1,1