Question

4. efetue as operações:


5. efetue como achar melhor:

${a)20x - (3x + 4)}^{2}$
${b)(7x - 4y)}^{3}$
$c)(7 - 9x).(7 + 9x)$




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Answer 1

Resposta:

Explicação passo-a-passo:

5x+x+y/x-y=

x-y(5x)+x+y/x-y

5x²-5xy+x+y/x-y

5x²-5xy

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5)

a) 20x-(3x+4)²

20x-3x²+2.7x+4²

20x-3x²+14x+16

-3x²+34x+16=0

-------------------------

b) (7x-4y)³

7x³+3(7x-4y)-4y³=0

7x³+21x-12y-4y³=0

7x³-4y³+21x-12y=0

------------------------

c) (7-9x) (7+9x)

7.7+7.9x-9x.7-9x.9x=0

49+63x-63x-81x=0

49+0-81x=0

-81x=-49 (-1)

x=49/81