Someone break down the 2 problems for me

Simply 8x squared + 5(7x squared- x) - 2x =

The graph of a function f(x)=(x+2)(x-4). which describes all of the values for which the graph is negative and increasing? all real values of x where x< -2 all real values of x where -2

If t8 = 4 and t12 = −2, find the first three terms of the arithmetic sequence.