Need help with revision from algebra:

Teachers message:

#5 - Please explain how you arrived at the equation 4.9 t²- 20 t = -(s-60).What does -(s-60) represent?

#8 - Please give an equation in the form ax²+ bx + c = 0 with numerical values for a, b, and c.

Original question:

5. A ball is launched upward at 20 meters per second (m/s) from a 60 meter tall platform. The equation for the object's heightsat timetseconds after launch iss(t) = -4.9t²+ 20t + 60, wheresis in meters.What is the maximum height of the object?

8)Give an example of a quadratic equation which would have only 1 solution. Write the equation in standard form.(You may not use an example from this lesson or any other lesson in this course.)

My answers:

s = shall be the height at which it is above ground

s = 60 + 20 t - 4.9 t²

at t = 0

s = 60

When will this reach the bleak on earth?

When s = 0

4.9 t²- 20 t -60 = 0

t = 6.09 or - 2.01

t = 6.09 will be used

(x-1)(x-b)=0

x-1=0

x-1+1=0+1

x=1

x-b=0

x-b+b=0+b

x=b

x=1, x=b

please write it out on computer, i cannot read handwriting.