Difference indicates subtraction: The difference of a number and 9 is (x−9) Twice the difference means 2(x−9) We know that the answer to this is 2 , so as an equation: 2(x−9)=2.
Set s(t) = 0 which means it hits the ground. The formula doesn't fit the parameters given as it shows that the pitcher is standing on something 37 feet high. <span>s(t)=-16t^2+140t+37 and has an initial velocity of 140. Graphing or solving this, t= 9 seconds when it hits the ground. The velocity V(t) is the derivative of s(t) V(t) = -32t+140 V(9) = -148 ft/second which is going down </span>