Find the least common denominator for these two rational expression a/a^2+2a+1 8/a^2+4a+3

The least common denominator of these two rational expressions is a^2.
Since none of the other terms are fractions, we assume that their denominators would be 1. We can’t multiply a^2 to every other numerator and denominator to make common denominators. You’re making it more complicated this way creating the fraction 1/a^2, which in its own gives the LCD a^2.