Question

Resolva os sistemas:

a) a + b = 15
a - b = 11

b) 3x - y = 7
x + y = 9

Answer 1

$a)2a = 26 \\ a = \frac{26}{2} \\ a = 13 \\ \\ a - b = 11 \\ 13 - b = 11 \\ b = 13 - 11 \\ b = 2 \\ logo \: a \: solucao \: da \: equacao \: s = (13 \: e \: 2) \\ \\ b)4x = 16 \\ x = \frac{16}{4} \\ x = 4 \\ \\ x + y = 9 \\ 4 + y = 9 \\ y = 9 - 4 \\ y = 5 \\ logo \: a \: solucao \: do \: sitema \: s = (4 \: e \: 5)$