Challenge Question: Here is a system with four linear equations.

x+a=6
x-b=5
x+c=4
x-d=3

what is the value of a+b+c+d

Me max recorded the heights of 500 male humans. he found that the heights were normally distributed around a mean of 177 centimeters. which statements about max’s data must be true? a) the median of max’s data is 250 b) more than half of the data points max recorded were 177 centimeters. c) a data point chosen at random is as likely to be above the mean as it is to be below the mean. d) every height within three standard deviations of the mean is equally likely to be chosen if a data point is selected at random.

X/y + 4y/x divided by x/y - 2y/x explain as in depth as you can how you simplfied the fractions. i don't know where to start on this : /

If each bricks costs and he can only buy one brick how much will it cost him to get the material to put around the outside of his garden?