Part A :A rocket scientist needs to find the overall thrust of a new rocket design. The rocket has two stages: Stage A and Stage B. Stage A’s thrust is defined by the expression 11.2x + 6.4 and Stage B’s thrust is defined by the expression 7.4x − 2.9. Part b: An engineer accidentally reads the blueprints incorrectly and installs the Stage B thrusters upside-down. What is the combined thrust of the rocket if Stage A is firing normally, but Stage B is applying reverse (negative) thrust?