Question

4x - y = 23x + 4y =27

Answer 1

4X - Y = 27 ===>  4X - 27 = Y

23X + 4Y = 27 ===> 23X + 4(4X - 27) = 27

23X + 16X -108 = 27

39X = 27 + 108:  39X = 135 ===>  X = (135/39) = 45/13

Reemplazamos X = 45/13 en 4X - Y = 27

4(45/13) - Y = 27

(180/13) - 27 = Y

Y = (180/13) - (351/13):  Y = -171/13

Rta X = 45/13 ,  Y = -171/13