Question

expand (2x-y+4)^3 help me plz..

Answer 1

Combine the 5th row of Pascal's triangle and a sequence of powers of 2 to find the coefficients of the expansion:

(2x+y)4=16x4+32x3y+24x2y2+8xy3+y4

Explanation:

Write out the 5th row of Pascal's triangle as a sequence:

1,4,6,4,1

Write out descending powers of 2 from 24 to 20as a sequence:

16,8,4,2,1

Multiply the two sequences together to get:

16,32,24,8,1

These are the coefficients of the expansion:

(2x+y)4=16x4+32x3y+24x2y2+8xy3+y4