Question

1) Determine o valor numérico das expressões algébricas

a) a³b – b², para A= –1 e B=2

b) (x–y).(y–2X), para X= 3 e Y= – 1/2

c) 
\sqrt{2x + y}2x+y​ 
para X= –2 e Y=8​

Answer 1

a)

${( - 1)}^{3} .2 - {(2)}^{2} = - 2 - 4 \\ = - 6$

b)

$(3 - ( - \frac{1}{2} ))( - \frac{1}{2} - 2.3) \\ = (3 + \frac{1}{2} )( - \frac{1}{2} - 6) \\ = \frac{7}{2}.( - \frac{13}{2} ) = - \frac{91}{4}$

c)

$(\sqrt{2x + y} )(2x + y) \\ = (\sqrt{2( - 2) + 8} )(2( - 2) + 8) \\ = \sqrt{4} .4 = 2.4 = 8$