The sum is 41.22 because first you turn all of the fractions into decimals and then it’s easier to add them all together all at once.
The time it takes to install 1 insulator would be 1.25 hours
Area = Length x Width
so, 88 = (something) x 8
Can you work out the something using mental math?
= 12*5 + 12*3i - 5*2i - 6i^2 (remember that i^2 = -1) so:-
= 60 +26i - 6*(-1)
= 60 + 26i + 6
= 66 + 26i
<span>the residuals for data set X do not form a pattern</span>