The coordinates of translations formulas
The values of the coefficients, a2 and a1 of the source quartic function y = a4x4 + a2x2 + a1x
The basic classification criteria diagram
The graphs of quartic functions and their characteristic points
The quartic  type 1,   y - y0 = a4(x - x0)4a2 = 0 and a1 = 0
The quartic  type 2,   y - y0 = a4(x - x0)4 + a1(x - x0)a2 = 0
The coordinates of translations formulas and the values of the coefficients of the source quartic function
 Thus,      y = a4x4 + a3x3 + a2x2 + a1x + a0    or    y - y0 = a4(x - x0)4 + a2(x - x0)2 + a1(x - x0), by setting  x0 = 0  and  y0 = 0 we get the source quartic   y = a4x4 + a2x2 + a1x.
The basic classification criteria diagram for the quartic function
By setting the coefficients a2 and a1 of the source quartic to zero, interchangeably, obtained is the basic classification shown in the diagram.
The graphs of quartic functions and their characteristic points
There are ten types (different shapes of the graphs) of quartic functions
 type 1 y = a4x4 + a3x3 + a2x2 + a1x + a0    or    y - y0 = a4(x - x0)4,  a2 = 0 and a1 = 0.
 The zeroes or roots:
 type 2 y = a4x4 + a3x3 + a2x2 + a1x + a0    or    y - y0 = a4(x - x0)4 + a1(x - x0),  a2 = 0.
 The zeroes of the source function:
 The zeroes of the translated function we get by adding x0 to the solution of the equation   a4x4 + a1x + y0 = 0.
Pre-calculus contents E