C.Add the following polynomials

1.4a+8b
-3a+15b=

2.3m+4n
-8m-2n=

3.9a+8b
-10b=

4.7x-9y
-8x=

5.(10a+llb)+(9a-14b)=

6.(7x²+2y²)+(2y²-5x²)=​