Question

01 – Descubra o valor das incógnitas nas equações abaixo

02 – Resolva os seguintes sistemas de equações do 1.º grau com uma incógnita por qualquer um dos métodos de resolução

Answer 1

Resolvendo:

I. a)

$4x+2=38\\4x=36\\x=9$

b)

$9a=6a+12\\3a=12\\a=4$

c)

$5n-1=3n+11\\5n-3n=11+1\\2n=12\\n=6$

d)

$2y+8=y+13\\2y-y=13-8\\y=5$

e)

$x+\frac{3x}{7} =10\\\\\frac{7x+3x=70}{7} \:\:\:.(7)\\\\7x+3x=70\\10x=70\\x=7$

f)

$\frac{x}{2} +\frac{x}{3} =35\\\\\frac{3x+2x=210}{6} \:\:\:.(6)\\\\3x+2x=210\\5x=210\\x=42$

g)

$3x-\frac{3}{4} x=45\\\\\frac{12x-3x=180}{4} \:\:\:.(4)\\\\12x-3x=180\\9x=180\\x=20$

h)

$\frac{x}{3} -\frac{x}{5} =16\\\\\frac{5x-3x=240}{15} \:\:\:.(15)\\\\5x-3x=240\\2x=240\\x=120$

II. a)

$\left \{ {{x-y=4\:\:-->\:\:x=4+y} \atop {2x-3y=6\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:\:}} \right. \\\\2x-3y=6\\2(4+y)-3y=6\\8+2y-3y=6\\-y=-2\\y=2\\\\x-y=4\\x-2=4\\x=6$

S = { (6; 2) }

b)

$\left \{ {{7x+y=38\:\:\:\:.(2)} \atop {x-2y=-16\:\:\:\:\:\:}} \right. \\\\\left \{ {{14x+2y=76} \atop {x-2y=-16}} \right. \\+-----\\15x=60\\x=4\\\\7x+y=38\\7\:.\:4+y=38\\28+y=38\\y=10$

S = { (4; 10) }

c)

$\left \{ {{x+y=5} \atop {x=2+y}} \right. \\\\x+y=5\\2+y+y=5\\2y=3\\y=\frac{3}{2} \\\\x=2+y\\x=2+\frac{3}{2} \\\\x=\frac{4+3}{2} \\\\x=\frac{7}{2}$

S = { (7/2; 3/2) }

Espero ter ajudado!

Desculpe qualquer erro.

Answer 2

Resposta:Resolvendo:

I. a)

b)

c)

d)

e)

f)

g)

h)

II. a)

S = { (6; 2) }

b)

S = { (4; 10) }

c)

S = { (7/2; 3/2) }

Espero ter ajudado!

Explicação passo a passo: