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Exercise 6

Solve each of the following systems:

a) [tex]\(\begin{cases} x + 2y = 1 \\ -3x + y = -10 \end{cases}\)[/tex]


Sagot :

Claro, resolveré el sistema de ecuaciones paso a paso:

Dado el sistema:
[tex]\[ \left\{\begin{array}{l} x + 2y = 1 \\ -3x + y = -10 \end{array}\right. \][/tex]

1. Multiplicamos la segunda ecuación por 2 para que el coeficiente de [tex]\( y \)[/tex] en ambas ecuaciones sea el mismo en valor absoluto:
[tex]\[ \left\{\begin{array}{l} x + 2y = 1 \\ -6x + 2y = -20 \end{array}\right. \][/tex]

2. Restamos la segunda ecuación de la primera para eliminar [tex]\( y \)[/tex]:
[tex]\[ (x + 2y) - (-6x + 2y) = 1 - (-20) \][/tex]
[tex]\[ x + 2y + 6x - 2y = 1 + 20 \][/tex]
[tex]\[ 7x = 21 \][/tex]

3. Despejamos [tex]\( x \)[/tex]:
[tex]\[ x = \frac{21}{7} = 3 \][/tex]

4. Sustituimos [tex]\( x = 3 \)[/tex] en la primera ecuación para encontrar [tex]\( y \)[/tex]:
[tex]\[ 3 + 2y = 1 \][/tex]
[tex]\[ 2y = 1 - 3 \][/tex]
[tex]\[ 2y = -2 \][/tex]
[tex]\[ y = \frac{-2}{2} = -1 \][/tex]

La solución del sistema es:
[tex]\[ x = 3 \quad \text{y} \quad y = -1 \][/tex]

Por lo tanto, la solución del sistema de ecuaciones es [tex]\( (x, y) = (3, -1) \)[/tex].