The problem actually starts at number 13! Because the answer is partially correct.
The explicit function for the sequence shown is actually y=-10 + -10(n-1)
The way to test out if that is the correct function is by testing if the first number is actually -10.
y= -10 + -10(1-1)
(Note: you plug in 1 into because we're testing the FIRST Number of the sequence.)
y= -10 - 10(0)
y= -10
It tested correct! Now let's make sure with the fourth sequence to ensure the function is correct. We'll do this by plugging in 4, and making sure we get -40.
y= -10-10(4-1)
y= -10-10(3)
y= -10-30
y=-40
Okay! So our function is correct. Now, we find the 50th number by plugging in 50.
y= -10-10(50-1)
y= -10- 10(50)
y= -10- 500
y= -510
So the answer to number 14 is -510!
Hope this helps. xx