This can be solved using the formula for t test which is = x - mu over standard deviation divided by the square root of the number of samples. In this case, it is 1185 - 1200 over 70 divided by square root of 100 which give us a value of 2.14 which is equal to .9839 in area. Only rarely, just over one time in a hundred tries of 100 light bulbs, would the average life exceed 1200 hours.
Answer: 
Step-by-step explanation:
1. To simplify the expression given in the problem, you must apply a property of exponents called Quotient of powers, which states that when you divide two powers that have the same base, you must subtract the exponents.
2. Keeping this property on mind you have, you can rewrite the expression as following and simplify:

Answer:
-538.67 (2 d.p)
Step-by-step explanation:
4x +1612 = x - 4
4x -x = -1616
x = (-1616)÷3= -538.67 (2d.p)
68
Schools almost over, good luck!!
Answer:
3rd 1 hope this helps
Step-by-step explanation: