jitu.js

var isPrime=function(x){
  for (var i = 2; i <= Math.sqrt(x); i++) {
    if(x%i==0){return false;}
  }
  return true;
}

var primeFactors=function(x) {
  var factors=[];
  for (var i = 2; i <= x; i++) {
    if(x%i==0 && isPrime(i)) {
      factors.push(i);
    }
  }
  return factors;
}

var canSheEqualise=function(a,xyz) {
  var allFactors={};
  var numberOfFactors={};
  a.forEach(function(i){
    primeFactors(i).forEach(function(p){
      allFactors[p]=true;
      numberOfFactors[p]=numberOfFactors[p]||0;
      numberOfFactors[p]+=1;
    });
  });
  var uncommonFactors=Object.keys(numberOfFactors).filter(function(n){
    return numberOfFactors[n]!=Object.keys(a).length;
  });
  var result=uncommonFactors.every(function(i){
    return xyz[i];
  });
  if(result)
    return "She can";
  return "She can't";
}

console.log(canSheEqualise([2,4],{2:true}));
console.log(canSheEqualise([2,3,6,7],{2:true,3:true}));
console.log(canSheEqualise([49,98],{2:true}));