C. CONCAVE
A mirror with a reflecting surface that caves inward is said to be CONCAVE.
Clue: caves inward. )(
Convex has an outline of surface that cave outward. It is like the outside of the circle or sphere. ()
The property shown in the following equation is 9 beacause simply we know 9=1 +8 so its easy
0=40-10t-5t^2
t^2+2t-8=0
(t+4)(t-2)=0
t=-4 (not a solution) or t=2
Answer: after 2 seconds
The answer is 31. 10+10+20+1=31
36v - 12 = 12 .....add 12 to both sides
36v - 12 + 12 = 12 + 12...simplify
36v = 24...divide both sides by 36
(36/36)v = 24/36
v = 2/3 <===