algebra help?

Question

fifth term of (2x-1)^7
tenth term of (4a+2b)^10

Answer 1

Assuming your first terms are (2x)^7 and (4a)^10 respectively, from the binomial theorm we have that the (j+1)th term of (a+b)^n is
(nCj) a^(n-j) b^j
So the fifth term of (2x-1)^7 is (7C4) (2x)^3 (-1)^4
= 35 (8x^3) (1)
= 280x^3.

Similarly, the tenth term of (4a+2b)^10 is
(10C9) (4a)^1 (2b)^9
= 10 (4a) (512b^9)
= 20480ab^9.

Answer 2

T(r+1)th term of (1-x)^n is (-1)^r* ncr *(x)^r
(1) (2x-1)^7
=-(1-2x)^7 {writing in standard form }
the firth term is as follows
r=4
T(4+1)th term is -{(-1)^4*7c4*(2x)^4}
=-35*16x^4 {the value of 7c4 = 35; (2x)^4=16x^4 }
=-560x^4
(2)(4a+2b)^10
t(r+1)th term of(x+y)^n is ncr *(x)^n-r*y^r
the tenth term is as follows
here r=9
=10c9*(4a)^1(2b)^9
=10*4a*512b^9
=20480b^9

Answer 3

http://www.wtamu.edu/academic/anns/mps/math/mathlab/col_algebra/col_alg_tut54a_seq.htm

This website tells you step by step. Just scrowl down to the sequence/terms.

Have fun!

Answer 4

Dont have a calculator???