Question

como faço a conta (3-a)^2 ​

Answer 1

$(3-a)^2~=~(3-a)\cdot(3-a)\\\\\\Utilizando~a~propriedade~distributiva~da~multiplicacao,~temos:\\\\\\(3-a)^2~=~3\cdot3~+~3\cdot(-a)~+~(-a)\cdot3~+~(-a)\cdot(-a)\\\\\\(3-a)^2~=~9~-~3a~-~3a~+~a^2\\\\\\\boxed{(3-a)^2~=~a^2~-~6a~+~9}$