Let n ∈ N. What is the smallest value of k such that every k-subset S of [n] has at least two 2-subsets {a, b} and {c, d} such that |a − b| = |c − d|?
(Here the two 2-subsets must be distinct, but they need not be disjoint

Use addition and subtraction to simplify the following polynomials. a. add polynomials: (3 – 4x + 8x^2) + (–6 + 2x – 5x^2) step 1: rewrite the polynomials without the parentheses. step 2: write the polynomial in descending order and use parentheses around like terms. step 3: add the like terms identified in step 2 to simplify the polynomial. b. subtract polynomials: (3x – 5 – 7x^2) – (–2 + 6x^2 – 5x) step 1: rewrite the polynomials without the parentheses. remember to multiply each term in the second parentheses by –1. show your work. step 2: write the polynomial in descending order and use parentheses around like terms. step 3: add the like terms identified in step 2 to simplify the polynomial.

What is r i 4.5+10r=-6.5 with work pls

Find the rate at which the water is now flowing from the tap give your answer cubic centimetres per second