ax2+bx+c is a polynomial in which variable

 x²+2x+1 is a polynomial in which variable

soln:-yes x²+2x+1 is a polynomial and it is quadratic polynomial and the quadratic polynomial is made by quad which means is square and it is variable of x.

     y²+2y+1 is a polynomial in which variable 

  soln:-yes y²+2y+1is a polynomial and it is quadratic polynomial and the quadratic polynomial is made by quad which means is square and it is variable of y.

  z²+2z+1 is a polynomial in which variable

 soln:-yesz²+2z+1is a polynomial and it is quadratic polynomial and the quadratic polynomial is made by quad which means is square and it is variable of z.