(4x-16) and (5x+7) of a triangle

Using elimination, what is -4x+2y=-12 4x+8y=-24

Which of these side lengths could form a triangle a) 2 cm , 2 cm , 4 cm b) 3 cm , 5 cm , 10 cm c) 3 cm , 4 cm , 5 cm d) 4 cm , 8 cm , 15 cm

A0.40 kg soccer ball is kicked so that its incoming velocity of 5 m/s is changed to an outgoing velocity of -25 m/s. what impulse does the player apply to the ball?