{[( A+2) x 2+2] x 2+2} x 2+2=30 {[( A+2) x 2+2] x 2+2} x 2=30-2 {[( A+2) x 2+2] x 2+2} x 2=28 {[( A+2) x 2+2] x 2+2} =28:2 [( A+2) x 2+2] x 2+2=14 [( A+2) x 2+2] x 2=14-2 [( A+2) x 2+2] x 2=12 ( A+2) x 2+2=12:2 ( A+2) x 2+2=6 ( A+2) x 2=6-4 ( A+2) x 2=2 A+2=2:2 A+2=1 A=1-2 A=-1