Find c such that (2,6), (−6,−1), and (c,3) lie on a line

Can any one me with the answers to these questions asap?

For each polynomial, determine the degree and write the polynomial in descending order. a. –4x^2 – 12 + 11x^4 b. 2x^5 + 14 – 3x^4 + 7x + 3x^3

The two square pyramids are similar. find the total volume of both pyramids if the ratio of their surface areas is 9/16