Answer:
I count 10 triangles.....
um
Step-by-step explanation:
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
x≤−11
−99≥18x−9x
−99≥9x
−
9
99
≥x
−11≥x
