Harshad,

I'll certainly help if I can. I hate to be picky, but in your example you have given a set of numbers {x1, x2}, rather than a list [x1,x2]. This difference does matter in STACK.

Are you using two answer boxes to let the student enter two numbers? If so, have one PRT where you use the AlgEquiv to test a set you make with {ans1,ans2} with another set made up of the teacher's answers. Of course, as you say order does matter.

I'm guessing that you are asking students to solve a quadratic equation. Is that correct? The student will provide a list/set of numbers and you need to check if they are correct and complete?

Well, in this case to check each element of the student's set/list satisfies the equation I'd suggest that you take each answer and see if it satisfies the equation by substituting in the value.

So, if (for argument's sake) you have a random quadratic expression

p:2*x^2+11*x-5/4

Then you can ev(p,x=ta1) and check algebraic equivalence with zero.

Asking students to solve equations is quite a common thing to want to do. So, rather than answer here I've add this as an example in STACK's documentation. See https://github.com/maths/moodle-qtype_stack/blob/master/doc/en/CAS/Equations.md

I've also added a new question to the sample questions folder illustrating this.

If this is *not* what you wanted to do, please try to describe it in more detail and I'll help.

Chris