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If d(t)=2t2+9t+3 is a function that gives the height of an object in feet as a function of time in seconds, find the interval of time when the object is above 7 feet. Use a graphing calculator or app to find the interval. E Show that each of the following functions is quadratic by writing the formula for each function in the form Ax2+Bx+C. Part A:f(x)=(7x8x2+3x3)/x Answer: Part B: g(x)=(9x6)(x+8) Answer: Part C: h(x)=6(x+1)26