Question

rezolvă sistemul de ecuații {X +2y=3 5X-y=-7​

Answer 1

Salut!

$\left \{ {{x+2y=3} \atop {5x-y=7}} \right. = \left \{ {{x=3-2y} \atop {5x-y=7}} \right. = \left \{ {{x=3-2y} \atop {5(3-2y)-y=-7=2}} \right. = \left \{ {{x=3-2y} \atop {15-11y=-7}} \right. = \left \{ {{x=3-2y} \atop {-11y=-22}} \right. = \left \{ {{x=3-2y} \atop {y=2} \right. = \left \{ {{x=3-2\cdot 2} \atop {y=2}} \right. = \left \{ {{x=-1} \atop {y=2}} \right.$

*Am folosit metoda substitutiei.

-Luke48

Answer 2

Aplic metoda substitutiei

x+2y= 3

5x-y = -7

x = 3-2y

5(3-2y)-y = -7

x = 3-2y

15-10y -y = -7

x = 3-2y

-11y= -22

x = 3-2*2

y= 2

x = -1

y =2