Question

Se 3a+8b=11 e a+6b=7 determine o valor a-b

Answer 1

3a+8b=11
a+6b=7 ---> a = 7-6b

3(7-6b)+8b=11
21-18b+8b=11
-18b+8b=11-21
-10b=-10 (.-1)
10b= 10
b= 10/10
b = 1

a = 7-6b
a = 7-6.1
a = 7-6
a = 1

a-b = 1-1 = 0