Answer:
z = 0
Step-by-step explanation:
3 (z + 7) = 21
3z + 21 = 21
3z = 0
z = 0
We can use ratios and the cross-multiply-divide to find this.
The ratio 21:5 is avaliable via the question. We then need to compare that to the ratio x:100, the 100 being the percent and the x being the number of airplane parts.
21/5 = x/100
We can then solve for x to find the number of airplane parts. First we multiply by 100 on both sides to get 2100/5 = x. Therefore x = 420 and there are 420 airplane parts.
Answer:

Step-by-step explanation:
Given
Let x represent the number of tickets, and p the charges

A reduction of 50c gives an increment of 50 tickets.
This gives:
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Required
Determine the demand function
First, calculate the slope:




So, the equation is:




Hence, the function is:

(x-1)^2=9 <=> x-1=3 <=> x=4