Answer:
Trapezoid.
Step-by-step explanation:
That is a trapezoid ( in the UK a trapezium).
There is a pair of parallel sides.
Answer: 
Step-by-step explanation:
Given
Half life of radioactive substance is 
Initial amount 
Amount left at any time is given by

It takes 26.4 days to reach 2 gm.
Step-by-step explanation:
x5 - 4x + 7x3 + 8 + 9x3 + 7x2 - 10 - 2x5 + 7x4 - 3x + 8
Arranging
x5 - 2x5 + 7x4 + 7x3 + 9x3 + 7x2 - 4x - 3x + 8 - 10 +8
-1 + 7x4 + 16x3 + 7x2 - 7x + 6
7x4 + 16x3 + 7x2 - 7x + 5
X = 9 is the correct answer