Question

can someone help me?
Automobile tire pressure increases about 1psi for each 10F increase in air temperature. At an air temperature of 55F a tires pressure is 30psi. Write an equation that models the tires pressure as a function of air temperature.

Answer 1

please can you people help me?

Answer 2

for each 10F increase in air pressure you have a 1 psi increase, so for each 1 increase in air pressure you have a \(\frac{1}{10}=0.1\) increase in psi
if you are going to write a linear equation we need the slope, and your slope is therefore \(0.1\)

Answer 3

ooh i think i get that but how would we find the y intercept?

Answer 4

at a pressure of 55 you get 30 psi, which is like saying the point \((55,30)\) is on the graph of your line

Answer 5

ooh so then we use the formula y-y1=m(x-x1) to get the y intercept right?

Answer 6

so you can use the "point-slope" formula to find the equation of your line.
the point is \((55,30)\) and the slope is \(0.1\)

Answer 7

yes you got it
go ahead and finish, i can check if you like

Answer 8

ok thank you!!!

Answer 9

yw

Answer 10

y=.1x+24.5? is that right?

Answer 11

that is what i get, yes.
you can also do the substitution trick
\(y=.1x+b\)
\(30=.1\times 55+b\)
\(30=5.5+b\)
\(b=24.5\)

Answer 12

ooh i will try that next time thank you so much!!

Answer 13

yw