CPM Homework Help : CCA2 Problem 10-146

Use the pattern for $(a + b)^5$ to write the fourth term of $(w - 4z)^5$ .

Step 1:

Using Pascal's Triangle, find the pattern for the $4$ ^th term of the $5$ ^th row.

Pascal's triangle, from rows, n, = 0, to n, = 5, where n, = 5, is 1, 5, 10, 10, 5, 1.

Step 2:

$10a^2b^3$

Step 3:

Substitute $w$ for $a$ and $-4z$ for $b$ and simplify.

Answer:

$-640w^2z^3$