Pretty lost on this. Can somebody help?

Instructions say: Add

0.15x^4 + 0.10x^3 - 0.9x^2
- 0.01x^3 + 0.01^2 + x
1.25x^4 + 0.11x^2 + 0.01
0.27x^3 + 0.99
-0.35x^4 + 15x^2 -0.03

Question

Pretty lost on this. Can somebody help? 

Instructions say: Add

0.15x^4 + 0.10x^3 - 0.9x^2
                - 0.01x^3 + 0.01^2 + x
1.25x^4                    + 0.11x^2        + 0.01
                    0.27x^3                          + 0.99
-0.35x^4                   + 15x^2          -0.03

unklerhaukus · Answer

add them all together?

unklerhaukus · Answer

well add the ...x^4 bits to each other, and add the x^3 bits together , etc

unklerhaukus · Answer

the x^4 bits sum to 1,
the x^3 bits sum to 0.36
the x^2 bits sum to 0.08
the x term is just 1
and the number 0.97

unklerhaukus · Answer

all together now
$$x^4+0.36x^3+0.08x^2+x+0.97$$

anonymous · Answer

The concept is adding the coeficient only when the term carry the same degree of variable x!

anonymous · Answer

Thank you both! I appreciate it! Helped me clear a few things up!

unklerhaukus · Answer

yeah you can only add  terms with the same variable (in this case powers of x