2
x +6x +8
2
x +8x+16

2
x +6x +8
2
x +8x+16

The way you tried to write out this equation makes it difficult to understand. If you mean this:


\frac { x^2 + 6x + 8} {x^2 + 8x + 16}


then you can factor both the numerator and denominator, and simplify from there. Non-permissible values are any values for x that make the denominator = 0.