Answer:
The answer is 0.
Step-by-step explanation:
Simply plug in -7 for x as they want to see what the value of the function is when x=-7.
You can then just add -7 and 7.
7 + -7 = 0
So the answer is 0
1. y+5=-x-5
2. y=-x-5-5
3.y=-x-10
4. y=x-10
_______________________
1. distribute negative sign
2. move the constant to the right and change the sign
3. -5-5 equals -10, bring everything down
4. change the sign of the x to positive, the equation is in standard form
F(x)=125-(125*0.2x)
to find the value of the phone after 3 years, you put x=3.
f(3)=125-(125*0.2(3))
f(3)=50