Question

Se s + t = 10 e mun = 8, determine o valor de sm + sn + tm + tn.​

Answer 1

$\large\boxed{\begin{array}{l}\underline{\rm fatorac_{\!\!,}\tilde ao~por~agrupamento}\\\sf \underbrace{\sf sm+sn}+\underbrace{\sf tm+tn}\\\sf s\cdot(m+n)+t\cdot(m+n)=(s+t)\cdot(m+n)\\\sf como~s+t=10~e~m+n=8~substitua:\\\sf 10\cdot8=80\end{array}}$