//Getting the input var a =Number(prompt("The general expression for quadratic equations is,\nax^2 + bx + c\nEnter a value for 'a'.")); var b =Number(prompt("The general expression for quadratic equations is,\nax^2 + bx + c\nEnter a value for 'b'.")); var c =Number(prompt("The general expression for quadratic equations is,\nax^2 + bx + c\nEnter a value for 'c'.")); //Delta function function delta(i,j,k){ return (j*j)-(4*i*k); } //Variables to shorten the code var d =delta(a,b,c); var e =((-b)/(2*a)); //Writing down the equation if(e!=NaN){ if(a!=1){ document.write("The roots of the quadratic equation "+a+"x"+"^"+2+""); }else{ document.write("The roots of the quadratic equation "+"x"+"^"+2+""); } if(b<0){ document.write(b+"x"); }else if(b>0){ if(b!=1){document.write("+"+b+"x"); }else{document.write("+"+"x"); } } if(c<0){ document.write(c+"=0"+" are:"+"
"); }else if(c>0){ document.write("+"+c+"=0"+" are:"+"
"); }else if(c==0){ document.write("=0 are:"+"
"); } } //The algorithm for getting delta out of the root. The heart of this code. for(x=Math.abs(d), lisT= [], ic=1, dis=1, i=2; i<=x;){ if((x==1) || (x==0)){break;} if(!(x%i)){ while(!(x%i)){ lisT[lisT.length]=i; x/=i;} if((lisT.length)%2==0){ for(j=1;j<=(lisT.length)/2;++j){ dis *=i;} } else{ for(j=1;j<=((lisT.length)/2)-1;++j){ dis *=i} ic *=i;} if(x!=1){lisT = [];} }else{i++;} } //Last two variables var f =dis/(2*a); var g =Math.abs(f); //Writing down the results. Longest part. It was REALLY long. if(d==0){document.write("x"+"_"+1+""+" = "+"x"+"_"+2+""+" = "+e); }else if(d>0){ if(e!=0){ if(ic==1){ document.write("x"+"_"+1+""+" = "+(e+f)+"
"+"x"+"_"+2+""+" = "+(e-f)); }else{ if(g!=1){ document.write("x"+"_"+1+""+" = "+e+" + "+g+"√"+ic+"
"+"x"+"_"+2+""+" = "+e+" - "+g+"√"+ic); }else{ document.write("x"+"_"+1+""+" = "+e+" + "+"√"+ic+"
"+"x"+"_"+2+""+" = "+e+" - "+"√"+ic); } } }else{ if(ic==1){ document.write("x"+"_"+1+""+" = "+(e+f)+"
"+"x"+"_"+2+""+" = "+(e-f)); }else{ document.write("x"+"_"+1+""+" = "+f+"√"+ic+"
"+"x"+"_"+2+""+" = "(-f)+"√"+ic); } } }else if(d<0){ if(e!=0){ if(ic==1){ document.write("x"+"_"+1+""+" = "+e+" + "+g+"i"+"
"+"x"+"_"+2+""+" = "+e+" - "+g+"i"); }else{ if(g!=1){ document.write("x"+"_"+1+""+" = "+e+" + "+g+"√"+ic+"i"+"
"+"x"+"_"+2+""+" = "+e+" - "+g+"√"+ic+"i"); }else{ document.write("x"+"_"+1+""+" = "+e+" + "+"√"+ic+"i"+"
"+"x"+"_"+2+""+" = "+e+" - "+"√"+ic+"i"); } } }else{ if(ic==1){ if(g!=1){ document.write("x"+"_"+1+""+" = "+f+"i"+"
"+"x"+"_"+2+""+" = "+(-f)+"i"); }else{ document.write("x"+"_"+1+""+" = "+"i"+"
"+"x"+"_"+2+""+" = "+"-i"); } }else{ if(g!=1){ document.write("x"+"_"+1+""+" = "+f+"√"+ic+"i"+"
"+"x"+"_"+2+""+" = "+(-f)+"√"+ic+"i"); }else{ document.write("x"+"_"+1+""+" = "+"+"+"√"+ic+"i"+"
"+"x"+"_"+2+""+" = "+"-"+"√"+ic+"i"); } } } } //Holy God, this was hard.

!ULTIMATE! Quadratic Equation Solver (including Complex Numbers)