Rewrite the problem with the term outside the parentheses distributed.
Example: 2(a+4b) is 2a+8b and -(3a-4) is -3a+4
Avoid Double signs in middle -3g(4h - 2) is -12gh+6g NOT -12gh--6g
See more examples at the bottom of the page
No Extra Spaces!
The checks are picky!
Must keep variables in same order to check!
So, 3x(2a - 5m) is 6xa-15ma BUT NOT: 6ax-15am [this is technically correct but it won't check!]
Watch your signs!
-3(-10a+5) is 30a-15
Do NOT combine like terms: If you get one like this: 2(3+4) the answer is 6+8
Use minus NOT plus negative.
So for 9k(10a+-2c)
Make sure you use 90ka-18kc NOT 90ka+-18kc. Once again, the second form is correct but it won't check.