por determinantes
y=20+5x
y=10x
acomodando
(y) (x). (r)
y-5x=20
y-10x=0
(x). (y)
∆| -5. 1 |. ((-5)(1))-((-10)(1)) = 5
|-10 1 |
(r. ) (y)
∆x |20. 1 |. ((20)(1)-(0)) =20
|0. 1 |
(x). (y)
∆y. | -5. 20| ((-5)(0)-(-10)(20))=200
|-10. 0|
x=∆x/∆
20/5= 4
y= ∆y/∆
200/5= 40
