Books spontaneously catch on fire in temperatures at or above 451, degree fahrenheit. write an inequality that is true only for temperatures (t)(t)left parenthesis, t, right parenthesis at which books spontaneously catch on fire.

For this case, the first thing you should do is define a variable.
 We have then:
 t: temperature (degree Fahrenheit).
 We write then the inequation that adapts to the problem:
 t> = 451
 
 an inequality that is true only for temperatures at which books spontaneously catch on fire is:
 t> = 451

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