7x-4y=5.... ..... --> y = (5-7x)/(-4)9x+8y = 13 ... --> y = (13-9x)/8Igualacion:(5-7x)/(-4) = (13-9x)/840 - 56x = -52 + 36x92 = 92 xx = 1y = (13 - 9(1) ) / 8y = 4 / 8y = 1/27x-4y=5 --> 7(1) - 4(1/2) = 59x+8y = 13 --> 9(1) + 8 (1/2) = 13