Hey there!

Firstly, we are going
add 
on each of the sides that we're working with. like ↓

This gives us

(if you are wondering how we got the out come of

it is because I
added 
Now
multiply 
on each of your sides
Cancel the first set and you will find the value of

Good luck on your assignment and enjoy your day ~
Answer:
1/3
Step-by-step
he flips the coin three time and there is one side so 1/3
Answer:
-1266
Step-by-step explanation:


I guess that u = μ & that a=σ. If so:
μ =100 & that σ =20 & x=20
Z score = (x-μ) / σ ==> Z score = (90-100)/20 ==> Z = - 0.5
The first one is the answer to the first question.
the second one is the answer to the second question