Question

5- Resolva o sistema de equações. {x+2y=10 2x- y=5 B){x-y=3 2x+y=12 c)y=2x+7 -6x- 2y=-4​

Answer 1

Resolvendo:

a)

$\left \{ {{x+2y=10\:\:\:\:\:\:\:\:\:\:\:} \atop {2x-y=5}\:\:\:\:\:\:.\:(2)} \right. \\\\\left \{ {{x+2y=10} \atop {4x-2y=10}} \right. \\+-----\\5x=20\\x=4\\\\x+2y=10\\4+2y=10\\2y=6\\y=3$

S = (4; 3)

b)

$\left \{ {{x-y=3} \atop {2x+y=12}} \right. \\+----\\3x=15\\x=5\\\\x-y=3\\5-y=3\\y=2$

S = (5; 2)

c)

$\left \{ {{y=2x+7} \atop {-6x-2y=-4}} \right. \\\\-6x-2y=-4\\-6x-2(2x+7)=-4\\-6x-4x-14=-4\\-10x=10\\x=-1\\\\y=2x+7\\y=2(-1)+7\\y=-2+7\\y=5$

S = (-1; 5)

Espero ter ajudado!

Desculpe qualquer erro.