Find the expansion of (x + y)⁴:

a) x⁴,x³y¹,x²y²,x¹y³,y⁴
1 way to get x⁴ (4) ways to get x³y¹
(1)
(4) ways to get x²y²
(2)
(4) ways to get x¹y³
(3)
1 way to get y⁴
x⁴+4x³y¹+6x²y²+4x¹y³+y⁴