Question

Suma y resta de ecuaciones x+4y=-21 10x+4y=42

Answer 1

10x + 4y= 42 x + 4y = -21 Restamos en vertical: (10x - x) + (4y - 4y)= (42 - (-21)) 9x + 0 = 42 + 21 9x = 63 x = 7 •Reemplazamos para hallar "y": • x + 4y = -21 7 + 4y = -21 4y = -21 -7 4y= -28 y = -7