Answer:
26: x=34
28: x=17
30: m=30
Step-by-step explanation:
<u>26:</u> 2x+22=90
subtract 22
2x=68
divide by 2
x=34
<u>28:</u> 18+3x+21=90
add 18 and 21
3x+39=90
subtract 39
3x=51
divide by 3
x=17
<u>30:</u> 43+87+m+20=180
add 43 and 87 and 20
m+150=180
subtract 150
m=30
The standard deviation is the square root of the variance
so if the variance is 256, then the standard deviation is : sqrt 256 = 16 <==
80. there's no mathematical equations, also there's nothing to compare
