Question

if discrimibant is larger than 0, there should be 2 solutions?

there are 2 solutions. 1.7 seconds and 3.29 seconds to hit 90 ft height. why pick 1.7 seconds, not 3.3 second? what does the graph look like?

4:05 Algebra 2 < Step 2 The Discriminant (D) ar? +bt+c = 0 of is D=b-4 2-4ac Substitute a =16, b = -80, c = 90 in D. D=(-80) - 4(16)(90) = 6400 - 5760 =640 >0 The discriminant is positive. The equation 90 = 801 - 161 has one real solution. Step 3 U = The roots of the equation ar? + bt+c=0 are -btvb2-4ac 2a 80+ 640 32 Substitute a = 16,b=-80, c=90 80–25.3 32 Simplify 80+25.3 80- 25.3 32 32 1 = 3.3,1 =1.7 Therefore, the object will reach at 1.7 sec height of 90 ft. Was this solution helpful? 0 Chapter 4.7 Problem 38E

Answer 1

Griven that, loo (205,100) go fct) = 8t- 16t2 So If height is go ft. t 1-7. 3.3 go=8+- 16t2 5. 10 - 16t²_8t+gozo fig: f(t)=87-16th = t=1.7, 3.3 (Provided in question Clearly from graph. in object will reach at lo7 sec of go ft a height li) It will go upto height 100 ft at 2.5 sec. lii) Then again it will come towards ground. at 3.3 sec it will be at go ft- Therefore, obiect reaches go ft. initically first at 17 see .ft.