Question

I understand it but then I don’t I think you you do y=mx + b could I get some help question 11 only

Answer 1

Given:

`h(x)=-10t^2+20t+80`

Where h(x) is the height of an object t second after launched

We will find the time (t) when hitting the ground.

So, the height will be = 0

substitute with h = 0 then solve the equation to find t

`\begin{gathered} -10t^2+20t+80=0\rightarrow(/-10) \\ t^2-2t-8=0 \\ (t-4)(t+2)=0 \\ t-4=0\rightarrow t=4 \\ t+2=0\rightarrow t=-2 \end{gathered}`

The negative result is illogical (there is no negative time)

So, the answer will be option D. 4