Answer:
f(x) = -x -1
Step-by-step explanation:
You can make the correct choice by seeing which equation works for the first line of the table.
f(-1) = -(-1) -1 = 0 . . . . . the first equation works
f(-1) = -(-1) +1 = 2 . . . not zero
f(-1) = -1 -1 = -2 . . . not zero
f(-1) = 1 -(-1) = 2 . . . not zero (same as second equation)
{(-2, 6), (-5, -1), (3, 7), (-5, 0)}
Domain: The domain is all the x-values (-2, -5, 3, -5)
Range: The range is all the y-values (6, -1, 7, 0)
Function: It's not a function because of the x-value -5 is repeating.
The y intercept will be 5
Do you remember when you were learning about
Least Common Multiple (LCM) ? And you were
wondering what on Earth you would ever need it for ?
THIS IS IT !
The amount of time after 8 PM when the lights will flash
together again is the LCM of 20 seconds and 30 seconds.
Do you remember how to find it ?
... When 20 is prime-factored, you have 2 · 2 · 5 .
... When 30 is prime-factored, you have 2 · 3 · 5 .
... So the Least Common Multiple of 20 and 30 is 2 · 2 · 3 · 5 = 60 .
The lighthouses will flash together again in 60 seconds after 8 PM.
That'll be 8:01 PM.
