2 Answers

(-10a)  .  When you know the value of "a", you can find the real value.  If a=6:

-10  x  6 =  -60    

HOWEVER, is a = (-6):

(-10)  x ( -6) = 60

See the result is very simple.

TIps- You should know the addition rule of integer.

Solution to the problem:

Question: ( - 4a) + ( -6a)

1. We can write  (-4a) as  -4a = (-a) + (-a) + (-a) +(-a) 

2. Similarly , we can write (-6a) = (-a) +(-a) +(-a) +(-a) +(-a) + (-a)

3. Then, ( - 4a) + ( -6a) = [(-a) + (-a) + (-a) +(-a)] + [ (-a) +(-a) +(-a) +(-a) +(-a) + (-a)]

Now, count the number of a , it is 10,

your result is    -10a.

Note: Remember! when we add , a +a, it is equal to 2a

i.e. a +a = 2a, in fact it is +2a 

We do not write the "+" sign if it comes first.

In the same way (-a) + (-a) = -2a

Hope this helped you to some extent. Now enjoy doing such kind of problems with your friends.