A mother decides to teach her son about a letter each day of the week. She will choose a letter from the name of the day. For ex
ample, on Saturday she might teach about the letter S or the letter U, but not the letter M. What letters are possible to teach using this method? (There are 15.) List all the letters in alphabetical order, with no spaces
Multiply both sides by 2. Move constant to the right-hand side and change the sign. Add the numbers. And change the signs on both sides of the equation.