Agrocer wants to mix x pounds of cashew nuts worth $7.00 per pound with 9 pounds of peanuts worth $3.00 per pound to obtain 9+x pounds of mixture worth $5.00per pound. total cost of cashews + total cost of peanuts = total cost.

Total cost of cashews + Total cost of peanuts = Total cost.
total cost of cashews=$7 * x=7x
total cost of peanuts=$3 * 9=27
total cost=(9+x) * $5=45+5x
7x+27=5x+45
subtract 5x from both sides:
2x+27=45
subtract 27 from both sides:
2x=18
x=9 pounds of cashews

The answer simplified would be. -6300x