Question

1. Resolva

a) 5 ( 4x - 9 + 6) = 0
b) 7 ( 2x - 5 + 3) = 0
c) 8 ( 7x - 3 + 10) = 0
d) 4 ( 5x - 7 + 2) = 0
e) 3 ( 2x - 6 + 9)= 0​

Answer 1

Equações de primeiro grau

Propriedade distributiva

Você multiplica o número que está na frente dos parenteses por todos  os elementos que estão dentro dos parenteses

Sempre obedecendo a regra de sinais

Na multiplicação

- x - = +

+ x + = +

- x + = -

+ x - = -

Observe que sinais iguais a resposta será POSITIVA

Já sinais diferentes a resposta será NEGATIVA

Ficando assim:

$a)5.(4x-9+6)=0\\\\\\20x-45+30=0\\\\\\20x-15=0\\\\\\20x=+15\\\\\\x=+\dfrac{15}{20} \\\\\\Simplicando\\\\\\x=+\frac{3}{4}$

$b)7.(2x-5+3)=0\\\\\\14x-35+21=0\\\\\\14x-14=0\\\\\\14x= +14\\\\\\x=+\dfrac{14}{14} \\\\\\x=+1$

$c)8.(7x-3+10)=0\\\\\\56x-24+80=0\\\\\\56x+56=0\\\\\\56x=-56\\\\\\x=-\dfrac{56}{56} \\\\\\x=-1$

$d)4.(5x-7+2)=0\\\\\\20x-28+8=0\\\\\\20x-20=0\\\\\\20x=+20\\\\\\x=+\dfrac{20}{20} \\\\\\x=+1$

$e)3.(2x-6+9)=0\\\\\\6x-18+27=0\\\\\\6x+9=0\\\\\\6x=-9\\\\\\x=-\dfrac{9}{6} \\\\\\Simplificando\\\\\\x=-\dfrac{3}{2}$

Bons estudos!

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