### Home > A2C > Chapter 12 > Lesson 12.4.1 > Problem12-161

12-161.

Use Pascal’s Triangle to expand $(x + y)^7$. Homework Help ✎

Recall Pascal's Triangle.
What row is needed to expand $(x + y)^7$?

Use the pattern for $(a + b)^7$.

$a^7 + 7a^6b + 21a^5b^2 + 35a^4b^3 + 35a^3b^4 + 21a^2b^5 + 7ab^6 + b^7$

Now substitute $x$ for $a$ and $y$ for $b$.