Respuesta :
We can translate the given data into points (hrs,inches). Hence, we have points (3,17) and (5,15). The rate at which the candle shortens is (15-17)/(5-3) equal to 1 inch per hour. Substituting this slope to the equation (y2-y1)= m(x2-x1) we have y-17= -1*(x-3) or y = -x + 20 where y is the length of the candle and x is the hours.
The generic equation of the line is:
[tex] H-H0 = m (T-T0) [/tex]
Where,
m: slope of the line
(T0, H0): ordered pair belonging to the line.
The slope of the line is:
[tex] m =\frac{H2-H1}{T2-T1} [/tex]
Substituting values we have:
[tex] m =\frac{15-17}{5-3} [/tex]
Rewriting:
[tex] m =\frac{-2}{2} [/tex]
[tex] m = -1 [/tex]
Then, choosing an ordered pair we have:
[tex] (T0, H0) :( 5, 15) [/tex]
Substituting values we have:
[tex]H-15=-(T-5)[/tex]
Rewriting the equation:
[tex]H-15=-T+5[/tex]
[tex]H=-T+5+15[/tex]
[tex]H=-T+20[/tex]
Then, for 8 hours we have:
[tex]H=-8+20[/tex]
[tex]H=12[/tex]
Answer:
a linear equation to model the relationship between height H of the candle, and T time is:
[tex]H=-T+20[/tex]
the candle will be 12 inches after burning 8 hours