I'll just do the first one. Here is Pascal's triangle
written to the 6th line:
1
1 1
1 2 1
1 3 3 1
1 4 6 4 1
1 5 10 10 5 1`
1 6 15 20 15 6 1
(3a2 + b)4
The two terms are (3a2) and (b).
The power is 4 so we will have 1 more term than the power, so
write those terms side by side 5 times skipping a space between
and on the left and right for coefficients and exponents. Put
+ signs between them:
(3a2) (b) + (3a2) (b) + (3a2) (b) + (3a2) (b) + (3a2) (b)
Put in exponents from 4 down to 0 on the (3a²)'s:
(3a2)4(b) + (3a2)3(b) + (3a2)2(b) + (3a2)1(b)3 + 1(3a2)0(b)4
Put in exponents from 0 up to 4 on the (b)'s:
(3a2)4(b)0 + (3a2)3(b)1 + (3a2)2(b)2 + (3a2)1(b)3 + (3a2)0(b)4
Put in the coefficients from the 4th line of Pascal's triangle, 1,4,6,4,1:
1(3a²)4(b)0 + 4(3a2)3(b)1 + 6(3a2)2(b)2 + 4(3a²)1(b)3 + 1(3a2)0(b)4
Simplify each term:
1·34a8·1 + 4·33a6·b + 6·32a4·b2 + 4·3a2·b3 + 1·1·b4
81a8 + 4·27a6·b + 6·9a4·b2 + 12a2·b3 + b4
81a8 + 108a6b + 54a4b2 + 12a2b3 + b4
Edwin