A chemistry student mixes two solutions to study the properties of the resulting mixture. The temperature of the new solution is given by the function T = 24t – 2t^2 + 5, where T is the temperature in degrees Celsius and t is the time elapsed in seconds after the solutions are mixed. What is the time interval that the temperature of the solution will be at least 69°C?

Intervals
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Question

A chemistry student mixes two solutions to study the properties of the resulting mixture. The temperature of the new solution is given by the function T = 24t – 2t^2 + 5, where T is the temperature in degrees Celsius and t is the time elapsed in seconds after the solutions are mixed. What is the time interval that the temperature of the solution will be at least 69°C?

Intervals
http://assets.openstudy.com/updates/attachments/51226a6de4b03d9dd0c59cf8-venom936-1361210356715-i.jpg

anonymous · Answer

@math>philosophy can you help me please

anonymous · Answer

Set T to 69 and find the roots. This will be your interval.

anonymous · Answer

$$69=24t -2t^2+5$$
Multiplt by -1
$$-69=-24t+2t^2-5$$
add 69 and rearrange
$$2t^2-24t+64=0$$