Question

A jeweler is heating a gold bar. It takes 7 joules of heat to raise the temperature of the bar 1º C. The initial temperature of the bar is 25ºC. Use this information to select the equation that corresponds to the information. y=7x+175y is equal to 7 x plus 175 y=7x−175y is equal to 7 x minus 175 y=25x−7y is equal to 25 x minus 7 y=7x−25

Answer 1

`y = 7x - 175`

Explanation:

Given

Initial temperature= 25ºC

Rise = 1ºC

Rate = 7 joules

Required

Determine the equation of the system

Let the final temperature be represented with x and the heat required be represented with y

This question will be solved using the following heat formula

`Heat\ Required = Rate * Change\ in\ Temperature`

`Heat\ Required = Rate * (Final\ Temperature - Initial\ Temperature)`

Substitute y for Heat Required; 7 for Rate; x for Final Temperature and 25 for Initial Temperature

`y = 7(x - 25)`

Open the bracket

`y = 7x - 7 * 25`

`y = 7x - 175`

Hence, the equation of the system is

`y = 7x - 175`