2(5a + 1) = 2(a + 1)
First we can divide both sides of the equation by 2:
2(5a + 1) = 2(a + 1)
(2/2)(5a + 1) = (2/2)(a + 1)
5a + 1 = a + 1
Now we can subtract 1 from both sides of the equation:
5a + 1 = a + 1
5a + 1 - 1 = a + 1 - 1
5a = a
Now we can see that this statement (5a = a) , is only true if a = 0 . However, if you can't see this straight away, then you can subtract 'a' from both sides of the equation:
5a = a
5a - a = a - a
4a = 0
Then you can divide both sides of the equation by 4:
(4a)/4 = 0/4
a = 0