We want to simplify the expression;
[tex]\begin{gathered} 6(5r-11)-1(5-r) \\ \text{Let's open the brackets, we would have} \\ 30r-66-5+r \\ \text{collect like terms to obtain} \\ 31r-71 \end{gathered}[/tex]So, the mistake you made is to forget to multiply the negative r by -1 when expanding.
- 1 x - r = + r
The equivalent expression is ,therefore , 31r - 71
