Practice problem
Which of these are quadratic expressions written in standard form?
x2+2x^2+2x2+2
3x−43x-43x−4
3x2+2x−33x^2+2x-33x2+2x−3
2x2−5x2x^2-5x2x2−5x
3x−2x2−13x-2x^2-13x−2x2−1
Type a concept, like “slope” or “photosynthesis”.