Question

Calcular a equação 5a+10b= 78 E 10a+30b= 179

Answer 1

5a + 10b = 78 ( multiplicar por - 2 )
10a + 30b= 179


- 10a - 20b = - 156
+10a +30b = 179
----------------------------
0 + 10b = 23
b = 23 /10

5a + 10b = 78
5a + 10•23 / 10 = 78 ( cancelar 10 )
5a + 23 = 78
5a = 78 - 23
5a = 55
a = 55 / 5
a = 11