Use Pascal’s Triangle to expand (x + y)7. Homework Help ✎
Recall Pascal's Triangle at right.
What row is needed to expand (x + y)7?
Use the pattern for (a + b)7.
a7 + 7a6b + 21a5b2 + 35a4b3 + 35a3b4 + 21a2b5 + 7ab6 + b7
Now substitute x for a and y for b.