8x + 9y = 3
9y = -8x + 3
y = -8/9x + 1/3...the slope here is -8/9. A parallel line will have the same slope....so any line parallel to 8x + 9y = 3 will have a slope of -8/9
1/5 becuase if you multiply by 5, it has to be 1, which means it has to be 1/5
17 subtracted from x is:
x-17
x-17 is AT LEAST 19, meaning your inequality sign is going to be a greater than or equal to sign, since it says AT LEAST.
Your expression will be:
x-17≥19
68% of the time, values will be within ONE std dev of the mean.
Thus, if the mean is 50 and the std. dev is 5, values will be between 45 and 55.
45 is one std dev below the mean, whereas 55 is one std dev above.
40 and 60 represent 2 std dev below the mean and above the mean, respectively. 95% of the time, values will be within the interval (40,60).
Here we're making use of the so called EMPIRICAL RULE.
99.9% of the time, values will lie within 3 std dev of the mean. This comes out to (45, 65). Unsure of how to conclude the 3rd question here.