The equation $$M$($x$,$y$)$equals$64$plus$0\mathrm{.}7$xminus$0\mathrm{.}1$y gives the mileage$($in mpg$)$ of a new car as a function of tire pressure x$($in psi$)$ and speed y$($in mph$).$ Find Upper M left parenthesis $27$ comma $54$ right parenthesis $($include the appropriate$$ units$)$ and explain what it means.

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Part $1$

Upper M left parenthesis $27$ comma $54$ right parenthesisequals

$$

$77\mathrm{.}5$

mpg

$($Type an integer or a$$ decimal.$)$

Part $2$

Explain what the answer in the previous step means. Select the correct choice below and fill in the answer boxes within your choice.

$($Type integers or$$ decimals.$)$

A$.$

Increasing the speed by one mph and maintaining a tire pressure of

$$

enter your response here psi will increase mileage by

$$

enter your response here mpg$.$

B$.$

Increasing the tire pressure by one psi and maintaining a speed of

$$

enter your response here psi will decrease mileage by

$$

enter your response here mpg$.$

C$.$

Increasing the tire pressure by one psi and maintaining a speed of

$$

enter your response here mph will increase mileage by

$$

enter your response here mpg$.$

D$.$

Mileage is

$$

enter your response here mpg at a tire pressure of

$$

enter your response here psi and a speed of

$$

enter your response here mph$.$

E$.$

Increasing the speed by one mph and maintaining a tire pressure of

$$

enter your response here psi will increase mileage by

$$

enter your response here mpg$.$