Question

(Binômios de Newton): Desenvolva (x-a)⁴

Answer 1

$(a-b)^n=\sum\limits_{k=0}^{n}\binom{n}{k}a^{n-k}*(-b)^k$

$(x-a)^4=\sum\limits_{k=0}^{4}\binom{4}{k}x^{n-k}*(-a)^k$

$(x-a)^4=\binom{4}{0}x^{4}*(-a)^0+\binom{4}{1}x^{3}*(-a)^1+\binom{4}{2}x^{2}*(-a)^2+\binom{4}{3}x^{1}*(-a)^3+\binom{4}{4}x^{0}*(-a)^4$

$\boxed{\boxed{(x-a)^4=x^{4}-4*x^{3}*a+6*x^{2}*a^2-4*x*a^3+a^4}}$

Só pra não ficar incompleta

$\binom{a}{b}=\frac{a!}{(a-b)!*b!}$