Solve for
:

Now if
, we have
and

On the other hand, if
, then
and

Since, the number w and 0.8 are additive inverses.
A number 'a' is said to have an additive inverse '-a' if "a+ (-a)= 0".
Since, 'w' and '0.8' are additive inverses of each other such that 
Therefore, the value of 'w' should be '-0.8' so that
.
So, the value of 'w' is =0.8
Now, Refer to the attached image which represents the position of 0.8 , w ( that is -0.8) and the sum of 0.8 and w.
Sum of 0.8 and w = 0.8 + w
= 0.8 +(-0.8)
= 0.
Answer:
Step-by-step explanation: Formula to find an area of a triangle A= 1/2base x height
Data
h=12mm A=1/2 base x height
b=14mm. A= 1/2 x (14mm x 12mm)
A=? A= 168mm^2(square) /2
A= 84mm square