Because the y value is the time it takes to complete 1 lap.
        
             
        
        
        
All these equations are in the form of ax^2 + bx + c = 0, where a, b, and c are some numbers. the discriminants of equations like this are equal to b^2 - 4ac. if the discriminant is negative, there are two imaginary solutions. if the discriminant is positive, there are two real solutions. if the discriminant is 0, there is one real solution.
<span>x^2 + 4x + 5 = 0
</span>b^2 - 4ac
4^2 - 4(1)(5)
16-20
-4, two imaginary solutions.
<span>x^2 - 4x - 5 = 0
</span>b^2 - 4ac
(-4)^2 - 4(1)(-5)
16 + 20
36, two real solutions.
<span>4x^2 + 20x + 25 = 0
</span>b^2 - 4ac
20^2 - 4(4)(25)
400 - 400
0, one real solution.
        
             
        
        
        
Answer:
523.6 cm^3
Step-by-step explanation:
We know the diameter is 10. The radius is half the diameter, so 10/2=5.
Knowing the radius is 5, we just need to plug it into the formula.
Volume=(4/3)pi5^3
≈523.6
Answer:523.6 cm^3
 
        
             
        
        
        
2y+18=42
2y=24
y=12
 Hope this helps!