Solve the problem.The half-life of an element is 4.2 × 1011 yr. How long does it take a sample of the element to decay to 
of its original mass? Use 
where A0 is the initial amount, T is the half-life, and t is the time. (Express results in scientific notation, rounded to the nearest hundredth.)
A. 1.49 × 1011 yr
B. 7.66 × 1010 yr
C. 3.22 × 1011 yr
D. 3.10 × 1011 yr
Answer: D
Mathematics
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Convert the equation given in rectangular form into polar form.4x - 9y + 14 = 0
A. r = 
B. r = 
C. 4 cos ? - 9 sin ? = 14
D. 4 cos ? - 9 sin ? = -14
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Solve the problem.Jim drove 117 miles in 3 hours. If he can keep the same pace, how long will it take him to drive 
A. 351 hr B. 60 hr C. 40 hr D. 30 hr
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Use the quadratic formula to solve the equation.
?
?
A. 
B. ?
C. ?
D. ?
E. ?
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Solve the problem.John does 8 pushups on the first day of a 30-day month, and then increases the number of pushups by 2 pushups a day. How many pushups has he done by the end of the month?
A. 1140 pushups B. 1110 pushups C. 1170 pushups D. 1102 pushups
Mathematics