what values of a,b, and c should be substituted in the quadratic formula or solve 5x^2-3x+2=0

why should it be substituted to solve

the quadratic equation is always in the form:
 
ax2 + bx + c
 
since your function is
 
5x2 - 3x + 2
 
 
a = 5
b = -3
c = 2
 
it should be substituted in the formula because you want to find the roots of this function when their factors are not that obvious to spot. in addition, even if you are able to factor using foil method, the first and last terms is no problem to obtain, but it is the outer and inner terms that will cause some obstacles when factoring.   also, since the formula has a plus and minus sign when finding the roots, you will have two solutions.  if the solutions are decimals, it is clear that standard factoring is almost impossible.