Question

resolva as equações do 1° grau , encontrando o valor das incógnitas : A) 7x-30=26 B) x÷4-3=4-x÷3 C) 9(x+2)=68-x D) 3x+5=x+13 E) 12(x-5)=4(x+20)

Answer 1

A)7x-30=26
7x=26+30
7x=56
x=56 ÷7
x=8

B) x:4-3=4-x
x÷4+x=4+3
x÷4+x=7
x+x=7.4
2x=28
x=28÷2
x=14

C)9(x+2)=68-x
9x+18=68-x
9x+x=68-18
10x=50
x=50÷10
x=5

D) 3x+5=x+13
3x-x=13+5
2x=18
x=18÷2
x=9

E) 12(x-5)=4(x+20)
12x-60=4x+80
12x-4x=80-60
8x=20
x=20÷8
x=2,5

Answer 2

7x-30=26
7x=26+30
7x=56
x=8
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$\frac{x}{4} .3 = 4 - \frac{x}{3} \\ \frac{3x}{4} = 4 - \frac{x}{3} \\ 9x = 48 - 4x \\ 9x + 4x = 48 \\ 13x = 48 \\ x = 3 \frac{9}{13} x = 369231$
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9(x+2)=68-x
9x+18=68x
9x+x=68-18
10x=50
x=5



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3x+5=x+13
3x-x=13-5
2x=8
x=4

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$12(x - 5) = 4(x + 20) \\ 12x - 60 = 4x + 80 \\ 12x - 4x = 80 + 60 \\ 8x = 140 \\ x = \frac{35}{2} \\ x = 17 \frac{1}{2} x = 17.5$