0,2(4b-9)+1,4b=0,6b+1,8;

Interpret decimal commas as decimal points. Solve:

0.2(4b − 9) + 1.4b = 0.6b + 1.8

• 0.2(4b − 9) = 0.8b − 1.8
• Left: 0.8b − 1.8 + 1.4b = 2.2b − 1.8
• Equation: 2.2b − 1.8 = 0.6b + 1.8
• Move terms: 1.6b − 1.8 = 1.8
• 1.6b = 3.6
• b = 3.6 / 1.6 = 2.25 = 9/4

Answer: b = 9/4 = 2.25.