Question

(Cotuca-SP) Determine os valores numéricos das expressões

a) xy²- x²y para × = - 1/2 e y = 2/3.​

Answer 1

Resposta:

$\Large \: x {y}^{2} - {x}^{2} y \: para \: x = - \frac{ 1}{2} \: e \: y = \frac{2}{3} \\ \\ \Large x {y}^{2} - {x}^{2} y = \\ \\ \Large \: = - \frac{1}{2} \sdot \left( \frac{2}{3} \right)^2 - \left( - \frac{1}{2} \right)^2 \sdot \frac{2}{3} \\ \\ \Large = - \frac{ 1}{2}\sdot\dfrac{4}{9} - \frac{1}{4}\sdot\dfrac{2}{3} \\ \\\Large= -\dfrac{4÷2}{18÷2}-\dfrac{2÷2}{12÷2} \\\\ \Large = -\dfrac{2}{9}-\dfrac{1}{6}\\ \\ \Large = \dfrac{-6\sdot2-9\sdot1}{54}\\\\\Large = \dfrac{-12-9}{54}\\\\ \Large = \dfrac{-21÷3}{54÷3}\\\\ \Large = \boxed{ \green{ \bf- \dfrac{7}{18}\: }} \\ \\ \Large \boxed{ \underline{ \blue{ \bf \: Bons \: Estudos!}}} \\ \\ \Large \boxed{ \underline{ \bf \: 22/05/2021}}$