Answer:
3.61 sec
Step-by-step explanation:
Set the given d= 3t + 3t ^2 equal to 50 and solve for t:
3t^2 + 3t - 50 = 0
This is a quadratic equation with coefficients 3, 3 and -50. The discriminant is b^2 - 4ac, or 3^2 - 4(3)(-50), or 9 + 600 = 609
The roots of this quadratic are therefore:
-(3) ± √609 -3 ± 24.68 21.68
t = -------------------- = ------------------- = ----------- = 3.61 sec
2(3) 6 6
