Hello,
x²-64=(x+8)(x-8)
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3z-4=6z-17
-3z-4=-17 (subtracted the 6z from both sides)
-3z=-13 (added the 4 to both sides)
z=

 (divided both sides by -3z)
z=
 
 
        
        
        
The video game is on 35% discount.
Step-by-step explanation:
Cost of video game = $50
Price on sale = $32.50
Amount of discount = Original price - price on sale

Percentage = 

The video game is on 35% discount.
Keywords: Percentage
Learn more about percentages at:
#LearnwithBrainly
 
        
             
        
        
        
The question might have some mistake since there are 2 multiplier of t. I found a similar question as follows:
The population P(t) of a culture of bacteria is given by P(t) = –1710t^2+ 92,000t + 10,000, where t is the time in hours since the culture was started. Determine the time at which the population is at a maximum. Round to the nearest hour.
Answer:
27 hours
Step-by-step explanation:
 Equation of population P(t) = –1710t^2+ 92,000t + 10,000
Find the derivative of the function to find the critical value
dP/dt = -2(1710)t + 92000
          = -3420t + 92000
Find the critical value by equating dP/dt = 0
-3420t + 92000 = 0
92000 = 3420t
t = 92000/3420 = 26.90
Check if it really have max value through 2nd derivative
d(dP)/dt^2 = -3420
2nd derivative is negative, hence it has maximum value 
So, the time when it is maximum is 26.9 or 27 hours