Is this expression a polynomial? if so classify it by its number of terms? 3x^2-5x

Yes,  3x^2-5x  is a polynomial.  it has two terms so it can be classified as a binomial. binomials are polynomials.

Event recording and direct observation methods

I'll do the first one for you. it isn't very hard at all.on number one, you have (50 × 3), which equals 150, and (3 × 3), which equals 9. after you establish that, you add 150 and 9 together. so, (150 + 9) equals 159.this means that 53 × 3 = 159.