Answer:

Step-by-step explanation:
Given the expression

Remove parentheses: (a)=a

Group like terms

Add similar elements
∵ 
Add similar elements
∵ 
Thus, the equivalent expression in simplified form:

P(z < x) = 0.6064 - 0.5 = 0.1064
From the normal distribution table
P(z < 0.27) = 0.1064
Therefore the z-score is 0.27
I can't explain it very well for you, sorry.