Example

Finding the Zeros and Specific Heights for h(t)=16t2+32t+128h(t) = -16t^2 + 32t + 128

To analyze the height of an object thrown upward, modeled by the polynomial function h(t)=16t2+32t+128h(t) = -16t^2 + 32t + 128, we can find its zeros, the time it reaches a specific height, and its height at a specific time. First, to find the zeros which indicate when the object hits the ground, set h(t)=0h(t) = 0. Factoring the equation 16t2+32t+128=0-16t^2 + 32t + 128 = 0 gives 16(t22t8)=0-16(t^2 - 2t - 8) = 0, which factors further to 16(t4)(t+2)=0-16(t - 4)(t + 2) = 0. This yields t=4t = 4 and t=2t = -2. Discarding the negative time, the object hits the ground at 4 seconds. Second, to find when the object is at a specific height of 128 feet, set h(t)=128h(t) = 128. Subtracting 128 from both sides gives 16t2+32t=0-16t^2 + 32t = 0. Factoring gives 16t(t2)=0-16t(t - 2) = 0, yielding t=0t = 0 and t=2t = 2. The object is at 128 feet at 0 and 2 seconds. Third, to find the height at a specific time, such as t=1t = 1 second, substitute 1 into the function. The result is h(1)=16(1)2+32(1)+128=144h(1) = -16(1)^2 + 32(1) + 128 = 144. The object is at 144 feet after 1 second, which is its highest point.

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Updated 2026-04-30

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