Question

Can you check my answers?

1.Use the Binomial Theorem to expand and simplify the expression.

(2 - 3x)3


-27x3 + 104x2 - 36x + 8

-27x3 + 54x2 - 36x + 8

-27x3 + 8

-27x3 + 54x2 - 18x + 8

answer:b

2.Find the 5th term in the expansion of the binomial.

(2x - 4)8


-458,752x3

286,720x4

458,752x3

35,840x4
answer: c

3.Find the 3rd term in the expansion of the binomial.

(x - 2y)12


264x10y2

1760x9y3

-264x10y2

-1760x9y3

answer: d

4.Find the coefficient of the term x2y6 in the binomial expansion of the expression (3x - 2y)8.


81,648

16,128

-81,648

-16,128

answer:c

Answer 1

#1 ok
#2 will be the x^4 term
#3 will be the x^10 y^2 term
#4 Nope. It is

8C6 (3x)^2 (-2y)^6
= 28*3^2*2^6 x^2y^6
= 16128 x^2y^6