Suppose securitex is a small firm that has developed a new anti-theft device for automobiles. securitex currently sells its device online and earns profit of $1515 million per year. gm is considering installing securitex's system on its automobiles. the two firms first, however, must bargain over what price gm will pay securitex for its software. gm chooses how much to offer securitex for its system and then securitex chooses whether to accept the offer and install its system on gm's automobiles. the strategies and corresponding profits for gm (gm) and securitex (sx) are depicted in the decision tree to the right. profits are in millions, and gm's payoffs represent the additional profit it can earn on its automobiles with securitex's anti-theft system. what is the subgame-perfect equilibrium