8. A firm has a production function Q  F(K, L) with constant returns to scale. Input prices are r  2 and w  1. The output-expansion path for this production function at these input prices is a straight line through the origin. When it produces 5 units of output, it uses 2 units of K and 3 units of L. How much K and L will it use when its longrun total cost is equal to 70?