QuadForm

print("Quadratic formula solver\nBoth the Lua and TI-Basic editions of this were written by EveryOS")
print("X=(-B+/-_/(B^2-4A(C-D)))/2*a\nAX^2+BX+C=D")
write("a: ")
local a = tonumber(read())
write("b: ")
local b = tonumber(read())
write("c: ")
local c = tonumber(read())
write("d: ")
local d = tonumber(read())
c=c-d
term.clear()
term.setCursorPos(1,1)
print("Please wait...")

local ipart = math.floor
local function getGCF(n1, n2)
  local f = 1
  for i = 1, n1 do
    if (n1/i == ipart(n1/i)) and (n2/i == ipart(n2/i)) then
      f = i
    end
  end
  return f
end

local function tofrac(a, b)
  if a == 0 then return "0" end
  if (b/getGCF(a, b))==1 then return tostring(a/getGCF(a, b)) end
  return tostring(a/getGCF(a, b)).."/"..tostring(b/getGCF(a,b))
end

d=b^2-4*a*c
local e = -b/(2*a)
if math.sqrt(d) == ipart(math.sqrt(d)) then
  print("X="..tofrac(math.sqrt(d)-b, 2*a).."\n -or-\nX="..tofrac(math.sqrt(d)+b, 2*a))
else
  local f = 1
  for i=1, d do
    if ipart(d/(i^2)) == d/(i^2) then
      f = i
    end
  end
  local str = tofrac(-b, 2*a).."+/-(" .. (((getGCF(f, 2*a)~=1) and getGCF(f, 2*a)) or "")..((d<0 and "i") or "").."_/"..math.abs(d)/(f^2)..")"
  if 2*a/getGCF(f,2*a) then
    str = str.."/"..tostring(2*a/getGCF(f,2*a))
  end
  print(str)
end