Solution:
Given:
Comparing the last row from the table,
[tex]\begin{gathered} 8(35+x)=70+9x \\ 280+8x=70+9x \\ Collecting\text{ the like terms,} \\ 280-70=9x-8x \\ 210=x \\ x=210 \\ \end{gathered}[/tex]
Therefore, Randall must use 210 pounds of $9 nuts for the mixture.
