Consider the following information:

Inverse market demand:P= 12 - 0.5(q₁+q₂), whereq₁andq₂are Firm 1's and Firm 2's output

Firm 1's reaction function:q₁= 9 - 0.5q₂

Firm 2's reaction function:q₂= 9 - 0.5q₁

The marginal cost of production for both firms is constant at $3. The equilibrium prices in Cournot and Stackelberg competition are _____ and _____, respectively.

$6; $5.25

$9; $10

$4; $3.50

$8; $7