I need step by step handwritten

7 How many solutions are there to the integer equation 1:: +32 +Is+14 = 15 subject to 1:1 2 0, 1:2 21, 1'3 2 2, 1:4 2 3? 8 What is the coefcient of 35y: in (2:: - y)\"'? 9 Compute 2:10 (?)3\""'(-2)", using the binomial theorem. 10 Show that, for integers 1 5 k 5 n, the identity 23;, (f) = (":1) holds and interpret this result with reference to Pascal's triangle