In the second step you should have subtracted the 2x to move it to the other or side of the equals sign
Answer:
After 3 seconds
Step-by-step explanation:
Given

Required
Time the drop will hit the ground
When the drop hits the ground,

So, we have:

Rewrite as:

Expand

Factorize

Factor out 5t + 1

Split
or 
Solve for t
or 
Time cannot be negative.
So:

Answer:
tip = $23.55
Step-by-step explanation:
156.98 x 0.15 = 23.55
Answer:
the second row is not a function! top row is a function
Step-by-step explanation:
because in order for it to be a function for every x there is exactly one y meaning there is no repeating x values! the second row had x = 5 twice, therefore they repeated x values meaning it's not a function