160, I think. SA=2(lw+lh+wh).
Answer:
Area of triangle: 1/2*base*height
Here height= 4
Base= 8
Thus area= 1/2*4*8
=4*4
=16
Step-by-step explanation:
1) -9 = 9 true/false
the answer is false because negative and positive quite unlike in terms.
2) -(-21) = -21
Using the symbols multiplication rule,
Where,
<h2>
+ × + = +</h2><h2>
- × - = +</h2><h2>
- × + = -</h2><h2>
+ × - = -</h2>
Therefore, -(-21) = +21 = 21
⟼ 21 = -21 
(18-7x)+1= -9 Hope this helps ^^