Question

Clare was solving an equation, but when she checked her answer she saw her solution was incorrect. She knows she made a mistake (or mistakes), but she can’t find where. Determine where and describe Clare's mistake(s). What is the correct solution to the equation?

Answer 1

the right solving is

`\begin{gathered} 12(5+2y)=4y-(5-9y) \\ 60+24y=4y-5+9y \end{gathered}`

the first mistake is multiplying 12x5, the right is 60 and Clare did 72

the second mistake is the negative sign on 9y, the sign change because the number was negative and the multiplication by negative sign , transform it to positive

now finish solving

`\begin{gathered} 24y-4y-9y=-60-5 \\ 11y=-65 \\ \\ y=-(65)/(11) \end{gathered}`