The result of this question is -23
# 3 is .4 because u multiply .2*.2
Answer:
x^4 - 81 = 0
(x² - 9)(x² + 9) = 0
Notice that the first of these is itself a difference of two squares:
(x - 3)(x + 3)(x² + 9) = 0
So the solutions are x = 3, x = -3, x = 3i, x = -3i
To find the specification limit such that only 0.5% of the bulbs will not exceed this limit we proceed as follows;
From the z-table, a z-score of -2.57 cuts off 0.005 in the left tail; given the formula for z-score
(x-μ)/σ
we shall have:
(x-5000)/50=-2.57
solving for x we get:
x-5000=-128.5
x=-128.5+5000
x=4871.50
The answer is x = 3.
Hope this helps (:
