If 2/3 of the cards are face-up, then 2/3*12=8 cards are face-up. The remaining 12-8=4 cards are therefore face down.
An obtuse angle!! It’s bigger than 90, but less than 180
Answer:
maximum :
a number infinitesimally larger than -29, or -28 if you prefer integers
minimum : 
negative infinity
Explanation:
if t + 31 < 2
than t + 31 - 31 < 2 - 31
t < -29

any number less than -29
ϵ just means infinitesimal small quantity denoted as 
Answer:
a=6
Step-by-step explanation:
hope this helps
Answer:
{1,4}
Step-by-step explanation:
A={3,6,9}
B={2,3,5,7}
C={1,2,3,4,5}
AUB={2,3,5,6,7,9}
(AUB)'={1,4,8,10}
(AUB)'⋂C={1,4}