I cant read this. This question is not in english.
a+b+c=9 and a2+b2+c2=35 then by using identity
(a+b+c)2=a2+b2+c2+2ab+2bc+2ca,we get the answer 9x9=35+2(ab+bc+ca)
2(ab+bc+ca)=9x9-35
2(ab+bc+ca) =81-35then we get ab+bc+ca=46/2 so ab+bc+ca=23
Answer: The mechanic worked for 4.25 hours for the fourth customer.
First find out the slope.
Y^2-y^1/x^2-x^1
210-90/3-1=60
Slope: 60
Then find out what the y-intercept is by plugging in values we know into y=mx+b
90=60(1)+b
30=b
Y=60x+30
Substitute the y with 285 to find out the x (hours)
285=60x+30
4.25=x
Color 4 boxes because 4/1 times 1/3 equals 4/3 witch is 4 boxes