Find the coefficient of x⁵ in the expansion of (1 + x)³ (1 – x)⁶.

To Find : coefficient of x⁵

For (1+x)³

a=1, b=x and n=3

We have a formula,

For (1-x)⁶

a=1, b=-x and n=6

We have formula,

We have a formula ,

By using this formula, we get,×

Coefficients of x⁵ are

x⁰.x⁵ = 1× (-6)=-6

x¹.x⁴ = 3×15=45

x².x³ = 3×(-20)=-60

x³.x² = 1×15=15

Therefore, Coefficients of x⁵ = -6+45-60+15 = -6

Conclusion : Coefficients of x⁵ = -6