Answer:
x = 45
y = 7
Step-by-step explanation:
To obtain the value of x and y, do the following:
√7 – 3√5
Rearrange
– 3√5 + √7
Multiply through by –1
3√5 – √7 ... (1)
Express 3√5 as a single surd
3√5 = √(3 × 3 × 5)
3√5 = √45
Replace 3√5 with √45 in equation 1
3√5 – √7
√45 – √7
Comparing
√45 – √7 and √x – √y i.e
√45 – √7 = √x – √y
x = 45
y = 7
The mean absolute deviation is 30
Answer:

Step-by-step explanation:
Given

Required
Find the equivalent
To find the equivalent of the given expression; we have to apply laws of indices;
As a law;

So; the expression
becomes

This is further simplified to


Combine to form a single fraction

Multiply numerator

The expression can not be further simplified
Hence
is equivalent to 
<span>half-life means you divide by 2
21.6 / 3.6 = 6 hf (hf = half-life)
then you divide by 2^6
6.02 x 10^23 / 2^6 = 9.40625 x 10^21 atoms
--------------
26
3hf ===> 2^3
10.0 / 2^3 = 1.25 gram (remaining)
answer : 10 - 1.25 = 8.75g
-------
27
128 / 2^n = 2
64 = 2^n
n = 6
24 /6 = 4
4 days is the half-live of the sample
-----------
28
2.5/4.46 of 50% initial mass
(2.5/4.46) x 0.5 x 2 = 0.5605 g
answer: 2 - 0.5605 = 1.4395 g
----------
29
2^7 = 128
so 7 half-lifes
7* 8040 = 56200 days
----------
30
the time of 10 half-lifes
= 10 x 0.334s = 3.34s </span><span>
</span>