Using the letters in the word forfeit, find the number of combinations that can be formed using 2 letters at a time.
a. 12
b. 19
c. 21
d. 41

Add the two expressions 3.8b - 7 and 2.9b + 9 enter your answer in simplified form

The ksp expression for the system pbcl2(s) pb+2(aq) + 2 cl-(aq) is: [pbc12][pb+2][2cl-] [pb+2][cl-]2 [pb+2][2cl-]2 [pbcl2][pb+2][cl-]2 [pb+2][2cl-]2[pbcl2]

Tim open up a new saving account with a $50 deposit and plant to deposit $20 per week into the same account.write an expression to represent the total amount in his savings account.