Fan and medal?

A science experiment begins with a metal at -100° Celsius. The following function describes the temperature change per minute: f(x) = 89x - 100°. How will the graph of this function change if the metal is at 25° at the start of the experiment?

Question

Fan and medal?

A science experiment begins with a metal at -100° Celsius. The following function describes the temperature change per minute: f(x) = 89x - 100°. How will the graph of this function change if the metal is at 25° at the start of the experiment?

anonymous · Answer

The line will shift vertically up by 125°.

 The line will shift vertically up by 25°.

 The line will shift vertically down by 125°.

 The line will shift vertically down by 25°.

aum · Answer

f(x) = 89x - 100°  is the equation of a straight line.
When x = 0, f(x) = -100 which is the starting temperature.  -100 is the y-intercept.

When the starting temperature is 25°, the function will change to:
f(x) = 89x + 25°
which will have a y-intercept of +25.

The first line has a y-intercept of -100
The second line has a y-intercept of +25

Both lines have the same slope of 89.

Therefore, the line has ..... ?

aum · Answer

|dw:1405988475631:dw|

anonymous · Answer

I'm sorry, I'm confused. I don't understand.

aum · Answer

Which part needs clarification?

anonymous · Answer

Really the whole thing. I read the chapter but I was confused. I called my teacher for help but she didn't understand.

anonymous · Answer

Sorry, she didn't pick up

aum · Answer

"A science experiment BEGINS with a metal at -100° Celsius."
"The following function describes the temperature change per minute: f(x) = 89x - 100°"

The second line tells us f(x) is temperature and x is time in minutes.
The first line tells us that when x = 0 (experiment BEGINS), temperature, f(x), = -100.

Clear so far?

anonymous · Answer

Yeah

aum · Answer

Original f(x) was f(x) = 89x - 100  (where the -100 was starting temperature).  That is, when x = 0, f(x) (which is temperature) = -100

"How will the graph of this function change if the metal is at 25° at the start of the experiment?"
f(x) will change to:  f(x) = 89x + 25   because when you put x = 0, you now get the temperature f(x) = +25.

Clear so far?

anonymous · Answer

Yeah. Sorry, but I have to go. I picked D as the answer, got it wrong. But I passed the test with a 90, this question being the only incorrect. I will give you a medal though for your time.

aum · Answer

The line will shift vertically up by 125°.