Question 11 Mark
Write first 4 terms in the expansion of $(2 x-3 y)^4$.
Answer
$\begin{aligned}(2 x-3 y)^4 & =(2 x)^4-{ }^4 C _1(2 x)^3 \cdot(3 y)+{ }^4 C _2(2 x)^2 (3 y)^2-{ }^4 C _3(2 x)(3 y)^3 \\ & =16 x^4-96 x^3 y+216 x^2 y^2-216 x y^3\end{aligned}$
View full question & answer→$\begin{aligned}(2 x-3 y)^4 & =(2 x)^4-{ }^4 C _1(2 x)^3 \cdot(3 y)+{ }^4 C _2(2 x)^2 (3 y)^2-{ }^4 C _3(2 x)(3 y)^3 \\ & =16 x^4-96 x^3 y+216 x^2 y^2-216 x y^3\end{aligned}$