What a polynomial is made of
A term is a single product of a number and variable powers: 7x³, −2x, and 5 are all terms. The number multiplying the variable is the coefficient; in −2x the coefficient is −2. A term with no variable, like 5, is the constant term. A polynomial is terms joined by + or −.
Why it works
The +/− signs are the seams that stitch terms together. Read 3x² − 5x + 4 as (+3x²) + (−5x) + (+4): a term always carries its own sign. That one habit makes subtraction painless later.