the half-life of a material is 4 hours. if the material starts with 300 mg, how much will remain after 20 hours?

9.375 mg will remain

hope that helped

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-13

step-by-step explanation:

f(x)=2x-5 for f(-4)

f(-4)   means let x=-4

f(-4) = 2(-4) -5

f(-4) =-8-5

      = -13