The first step in solving the exercise is to replace the given value of b into the equation:
[tex]\begin{gathered} 65\div b+8\cdot4=20 \\ \frac{65}{b}+8\cdot4=20 \\ \frac{65}{5}+8\cdot4=20 \end{gathered}[/tex]
Now, we follow the PEMDAS order, that is, first multiplications and divisions and then the addition:
[tex]\begin{gathered} \frac{65}{5}+8\cdot4=20 \\ 13+32=20 \\ \boldsymbol{45\neq20}\text{ }\Rightarrow\text{ "}\ne\text{" reads "different"} \end{gathered}[/tex]
Finally, since 45 is different from 20, then the given value of the variable is not a solution to the equation.
