5x + 7y = 183x - 5y = 20hallar : "xy"7x + 5y = 113x + y = 7hallar : "y"elevadoa" x"?

X = (18 - 7y) / 5

X = (20 + 5y) / 3

Igualando

(18 - 7y) * 3 = (20 + 5y) * 5

54 - 21y = 100 + 25y - 46 = 46y

Y = - 1

X = (18 - 7( - 1)) / 5

X = 25 / 5

X = 5

X * Y = 5 * - 1 = - 5

7x + 5y = 11

3x + y = 7

X = (11 - 5y) / 7

X = (7 - y) / 3

Igualando

(11 - 5y) * 3 = (7 - y) * 7

33 - 15y = 49 - 7y - 8y = 16

Y = - 2

X = (11 - 5( - 2)) / 7

X = 21 / 7

X = 3

Y elevado a la x

( - 2) ^ 3 = - 8.