What is the sum of
(9c - 8d) + (2c - 6) + (-d + 3)

Is the open sentence 5x-2=3x+2 true when x=2? justify your answer.

Solve this riddle: i am an odd number. i an less than 100. the some of my digit is 12. i am a multiple of 15. what number am i?

Find a third-degree polynomial equation with rational coefficients that has roots -2 and 6+i