Question

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Qual o valor de x nas equações :

a) 5x +15 = x - 12 +2x b) -15 – 3x – 2 ( x+4)= x + 4 ( 2 + x)
c)1/4 +3x = 2x/8 – 3/2

Resolva as inequações do 1 grau
a) 4x -10 < 3x + 20 b) 10-2 ( 3x +1 ) > 3( x -3)
c) -4 + 2x/5 < 6/10 + 3x

Resolva os sistemas de equação do 1 grau:
a) 2x + y = 8 b) x = 2y + 10
3x -y = 12 2x +3Y= 6​

Answer 1

Resposta:

Olá!

Explicação passo-a-passo:

1. a) $5x+15=x-12+2x$

$5x-x-2x=-12-15$

$2x=-27$

$x=-\frac{27}{2}$

b) $-15-3x-2.(x+4)=x+4.(2+x)$

$-15-3x-2x-8=x+8+4x$

$-3x-2x-x-4x=8+15+8$

$-10x=31.(-1)$

$10x=-31$

$x=-\frac{31}{10}$

c) $\frac{1}{4}+3x=\frac{2x}{8} -\frac{3}{2}$

$3x-\frac{2x}{8} =-\frac{3}{2} -\frac{1}{4}$

$\frac{24x-2x}{8} =\frac{-6-1}{4}$

$\frac{22x}{8} =\frac{-7}{4}$

$22x.4=-7.8$

$88x=-56$

$x=-\frac{56}{88}$

$x=-\frac{7}{11}$

2. a) $4x-10<3x+20$

$4x-3x<20+10$

$x<30$

b) $10-2.(3x+1)>3.(x-3)$

$10-6x-2>3x-9$

$-6x-3x>-9-10+2$

$-9x>-17.(-1)$

$9x<17$

$x<\frac{17}{9}$

c) $-4+\frac{2x}{5}<\frac{6}{10} +3x$

$\frac{2x}{5}-3x<\frac{6}{10} +4$

$\frac{2x}{5}-3x<\frac{3}{5} +4$

$\frac{2x-15x}{5}<\frac{3+20}{5}$

$\frac{-13x}{5}<\frac{23}{5}$

$-13x.5<23.5$

$-65x<115.(-1)$

$65x>-115$

$x>-\frac{115}{65}$

$x>-\frac{23}{13}$

3. a) $\left \{ {{2x+y=8} \atop {3x-y=12}} \right.$

$2x+y+(3x-y)=8+12$

$2x+y+3x-y=8+12$

$2x+3x+y-y=20$

$5x=20$

$x=\frac{20}{5}$

$x=4$

$2.4+y=8$

$8+y=8$

$y=8-8$

$y=0$

b) $\left \{ {{x=2y+10} \atop {2x+3y=6}} \right.$

$\left \{ {{x-2y=10} \atop {2x+3y=6}} \right.$

$\left \{ {{x-2y=10.(3)} \atop {2x+3y=6.(2)}} \right.$

$\left \{ {{3x-6y=30} \atop {4x+6y=12}} \right.$

$3x-6y+(4x+6y)=30+12$

$3x-6y+4x+6y=30+12$

$3x+4x-6y+6y=42$

$7x=42$

$x=\frac{42}{7}$

$x=6$

$3.6-6y=30$

$18-6y=30$

$-6y=30-18$

$-6y=12.(-1)$

$6y=-12$

$y=-\frac{12}{6}$

$y=-2$

Bons Estudos!