Question

3a + 5b - ab, para a = 2 e b = -3

Answer 1

Substituindo os valores de "a" e "b" na expressão dada:

$3a+5b-ab~=\\\\\\=~3\,.\,(2)~+~5\,.\,(-3)~-~(2)\,.\,(-3)\\\\\\=~6~-~15~-~(-6)\\\\\\=~6~-~15~+~6\\\\\\=~\boxed{-3}$