Sue's sushi placed two orders with its fish supplier. one order was for 11 pounds of salmon and 6 pounds of tuna; the order totaled $157. the other order was for 8 pounds of salmon and 4 pounds of tuna; this order totaled $112. what is the cost for one pound of salmon and one pound of tuna?

S is salmon price per pound (in dollars)
t is tuna price per pound (in dollars)

Order One: 11s + 6t = 157
Order Two: 8s + 4t = 112

You have three choices:
substitution - solve one equation for a either variable and substitute into the other equation
Add (or subtract) equations to eliminate one variable. (Usually must multiply eq. First)
Solve each equation for One variable and graph (doesn’t work non-integer values)

I’ll attach a copy of the work.