4/11a +a

Likely interpretation: (4/11)a + a

• Combine like terms: a*(4/11 + 1) = a*(4/11 + 11/11) = a*(15/11)
• Result: 15a/11

If you instead meant 4/(11a) + a (less common):

• Put over a common denominator 11a: a = 11a^2/(11a)
• Then (11a^2 + 4)/(11a)

So the answers are:

• (4/11)a + a = 15a/11
• If it was 4/(11a) + a, then (11a^2 + 4)/(11a)

Which interpretation did you intend?