Question

The speed of a toy car over time can be represented by a parabola with minimum speed 2 m/s after 3 seconds. After 5 seconds, the car's speed is 3 m/s. What is the equation in vertex form of a parabola that represents the car's speed, y, over time, x?

Answer 1

You have to solve x multiplying y

Answer 2

Explanation:

y=ax²+bx+c

x=0,y=0,c=0

y=ax²+bx

2=9a+3b (×-5)

3=25a+5b(×3)

add

9-10=75a-45a+15b-15b

30a=-1

a=-1/(30)

2=9×(-1/30)+3b

3b=2+3/10=23/10

b=23/30

y=-1/30 x²+23/30=-1/30(x²+23x+(23/2)²)+1/30 ×(529/4)

y=-1/30(x+23/2)²+529/120