please step by step, explain in detail, first time taking this

Exercise 2 We want to solve the system Ax=b, where A=d1a100c1d2a20c2d30an100cn1dn,x=x1x2xn1xn,andb=b1b2bn1bn The matrix A is called tridiagonal. An improvement of the naive Gauss elimination yields the algorithm below (the function "tri" to the right) a) Count the number of FLOPS in the function tri b) Use function tri to solve Ax= b, where A=2100121001210012,andb=45102