Im gonna take an educated guess on this. for the first part only one element has an outershell filled completely. but if they want two elements put chlorine. to lose electrons is probably helium to gain is magnesium. and the last one is lithium and helium because they're small and don't have allot of atomic mass
The answer is 31
29 - 13 is 16
16 + 15 is 31
Step-by-step explanation:
First factor out the negative sign from the expression and reorder the terms
That's

<u>Using trigonometric </u><u>identities</u>
That's
<h3>

</h3>
<u>Rewrite the expression</u>
That's

We have
<h3>

</h3>
<u>Rewrite the second fraction</u>
That's
<h3>

</h3>
Since they have the same denominator we can write the fraction as

Using the identity
<h3>

</h3>
<u>Rewrite the expression</u>
We have
<h3>

</h3>
<u>Using the trigonometric identity</u>
<h3>

</h3>
<u>Rewrite the expression</u>
That's
<h3>

</h3>
Which is
<h3>

</h3>
<u>Using the trigonometric identity</u>
<h3>

</h3>
Rewrite the expression
That's
<h3>

</h3>
<u>Simplify the expression using symmetry of trigonometric functions</u>
That's
<h3>

</h3>
<u>Remove the parenthesis </u>
We have the final answer as
<h2>

</h2>
As proven
Hope this helps you
Answer:
18/38 or 9/19
Step-by-step explanation:
18 squares are red
18 squares are black
2 squares have 0 or 00