Question

86x + y = 500 5x - 7y - 800 = 0

Answer 1

Despejando x de la primera
X=(500-y) / 86

Despejando y de la 2a
y= (800-5x) / 7

Sustituyendo y en x
X= 500\86 - ((800-5x)/7)/7
x = 500/86 - (800/7)/7 + (5x/7)/7
x = 500/86 - 809/14 + 5x/14
X( 1 - 1/14) = 5.81 + 57.14
X = (62.95) / ( 1-1/14)
X= 62.95 / 0.93
X = 67.68

Y= (800-5(67.68))/7
Y= 65.93