\(a,0,08\times a=1,2\times100\\ \Rightarrow0,08\times a=120\\ \Rightarrow a=120:0,08\\ \Rightarrow a=1500\\ b,2,6:\left(3,7-a\right)=1\\ \Rightarrow3,7-a=2,6:1\\ \Rightarrow3,7-a=2,6\\ \Rightarrow a=3,7-2,6\\ \Rightarrow a=1,1\)
0,08 × a = 1,2 × 100
=>0,08x a=120
=>a=120:0,08
=>a=1500
2,6 : (3,7 – a) = 1
=>3,7-a=2,6:1
=>a=3,7-2,6
=>a=1,1