Algebra help needed

Question

 For what values of x is a rational expression undefined?

Answer 1

In order to find values for which a given expression is undefined, we set the denominator equal to 0 and solve.

Thus:(x²+1)(x+2)=0. Now we use the fact that a product is equal to zero if one piece or the other or both are equal to zero. So we set x²+1=0 and x+2=0. The first gives us x²=-1 or x=+-i, but depending on what your instructor is asking for, we may not use this part because it is complex. The second gives us x=-2.

Answer 2

x = - 2 makes this expression undefined because if you plug x = - 2 into the express will makes denominator zero.