#### rocketsonly

##### Well-Known Member

- Joined
- Apr 7, 2004

- Messages
- 881

- Reaction score
- 0

a + b = c

Form two separate equations, and multiply one by 4, and the other by 5.

4a + 4b = 4c .............. 5a + 5b = 5c

Subtract 4c from both sides on the first equation, and subtract 5c from both sides on the second equation.

4a + 4b 4c = 0 ................. 5a + 5b 5c = 0

Because both now equal 0, they must equal the same.

4a + 4b 4c = 5a + 5b 5c

Factor out the 4 on one side, and the 5 on the other.

4(a + b c) = 5(a + b c)

Now divide each side by a + b c

4 = 5

Cool eh?

Can someone spot the mistake?

EDIT: spacing not correct