Step-by-step explanation:
Ex. 4 (2n- 5) = 3n + 10
So since there is a number outside the parenthesis (which is in the first term) You have to distribute the number by multiply 4 to 2n and to -5.
(4*2n) (4*-5) = 6n - 20 (ALWAYS Carry the negative sign when you have a negative answer.)
Then, Do the addition/subtraction property which would be:
6n - 20 = 3n + 10
-3n +20 -3n + 20
3n = 30
/3 /3
n = 10
Hopefully this helps.