# Tutor profile: Olivia P.

## Questions

### Subject: Pre-Algebra

What is order of operations and is there an easy way to remember it?

Order of operations is a set of rules for the correct order to solve a math equation when there are multiple steps involved (ex. subtraction and division). An easy way to remember order of operations is with the phrase "Please Excuse My Dear Aunt Sally". The letters in this phrase give the correct order for operations. Please: parenthesis, any operation inside parentheses should be done first. Excuse: exponents should be next. My Dear: multiplication and division come next. Aunt Sally: addition and subtraction are the last steps

### Subject: Biology

What is the plasma membrane of an animal cell?

The plasma membrane (also called the cell membrane) is a phospholipid bilayer that surrounds the cell. This means there are two layers of phospholipids (each having a hydrophobic tails and hydrophilic heads) providing protection for the contents of the cell. This structure also allows for the movement of certain nutrients/substances through the membrane.

### Subject: Algebra

What is the difference between log and ln?

log refers to a logarithm with base 10. Log(x) tells you to what power you must raise 10 in order to get x (ex. log100=2 because 10^2=100). Whereas ln is the same as writing logarithm with base e. Ln(y) tell you to what power you must raise e in order to get a result of y (ex. ln(e)=1 because e^1 = e).

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