Question

As tres prfv...Pra agora,me ajudem

Answer 1

Resposta:

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Explicação passo-a-passo:

3.

$Z = \frac{3i}{1+i}\\Z = \frac{3i}{1+i}.\frac{1-i}{1-i}\\Z = \frac{3i -3i^2}{1-i^2}\\Z = \frac{3i-3.(-1)}{1-(-1)}\\Z = \frac{3i+3}{2}\\Z = \frac{3}{2}+\frac{3}{2}i$

4.

$(a+b.i)-(a-b.i) = 6.i\\a +b.i -a +b.i = 6.i\\2.b.i = 6.i\\b = \frac{6.i}{2.i}\\b = 3\\\\Z = 3.i$

5.

$( 4 +i).( x -2y) = y +\frac{i}{2} \\4.x -8.y +x.i -2.y.i = y +\frac{i}{2}\\(4.x -8.y) +(x -2.y).i = y + i.\frac{1}{2}\\ \\\left \{ {{4.x-8.y = y} \atop {x - 2.y = \frac{1}{2} }} \right. \\\\4.x = 9.y\\x = \frac{9.y}{4} \\\\\frac{9.y}{4}-2.y = \frac{1}{2}\\\frac{9.y-8.y}{4}=\frac{1}{2}\\2.y = 4\\y = 4/2\\y = 2\\\\x = \frac{9.2}{4}\\x = \frac{9}{2}$

Dúvidas só perguntar XD