We are going to solve the equation step by step and you can compare and find the step where nisha make her first error..
[tex]\begin{gathered} \text{step 1} \\ 7b+3.2b-5-18.92=0 \\ \text{step 2: we }group\text{ the similars in parentheses and operate} \\ (7b+3.2b)+(-5-18.92)=0 \\ \text{step 3: } \\ (10.2b)+(-23.92)=0 \\ \text{step }4\colon\text{ we solve to b} \\ 10.2b=23.92 \\ b=\frac{23.92}{10.2}=2.34 \\ b=2.34 \end{gathered}[/tex]Finally, comparing two solution process we conclude that the step where Nisha made her first mistake was 3rd step.
