Question

5x +6y = 20 (1)

Al resolver el siguiente sistema de ecuaciones


los valores de las incógnitas son:

(4x-3y=-23 (2)

a) x= 2; y= -5

b) x= 13;y=1

c) x= -2; y= 5

Answer 1

c) x = -2; y = 5

Explanation:

4x - 3y = - 23 multiply by 2

8x - 6y = - 46

+ 5x + 6y = 20 add the two equations

13x + 0y = -26 divide by 13

x = -2 enter x into either original equation

5(-2) + 6y = 20

-10 + 6y = 20

6y = 30

y = 5

Answer 2

(2) + (2)

=> 8x - 6y = -46 ———(3)

(1) + (3)

=> 5x + 6y + (8x - 6y) = 20 - 46

=> 13x + (6-6)y = -26

=> 13x + 0y = -26

=> 13x = -26

=> x = -26/13

=> x = -2

=> 5(-2) + 6y = 20

=> 6y = 20 + 10

=> 6y = 30

=> y = 5

x = -2, y = 5 => C