ummmmmmmm Maybe 350 I think
The least-square regression line has a slope of:
m=(nΣxy-ΣyΣx)/(nΣx²-ΣxΣx)
and a y-intercept of:
b=(Σy-mΣx)/n
In this case: n=7, Σxy=4899, Σy=391, Σx=85, Σx²=1153 so
m=(7(4899)-391*85)/(7(1153)-85*85))=1058/846
b=(391*846-85*1058)/(7*846)=34408/846
So the line of best fit is:
y=(1058x+34408)/846 and if we approximated this as your answers see to have done....
y=1.25x+40.67
the answer would be A.
7x × X gives you 7x^2
7x × 2 gives you 14 X
so the answer is the square root of 7x^2 + 14 X
$20×.25=$5
$20-$5=$15
$15×.15=$2.25
$15+$2.25=$17.25
$17.25 is your answer
