I have a math test and I don't know how to do a question that says solve H=-b/2a for b

Question

Solve H=-b/2a for b

that's all I have for the question and it doesn't explain much but that's all there is.

I've look up other ways but it doesn't tell me the exact answer just tell me to cross multiply but I don't know how to do that with this problem.

Answer 1

h(t) = -16t^2 + vot +ho

is the general equation.

take the first derivative and set =0

h'(t) = -32t + vo = 0

t = vo/32

h(vo/32) = -16(vo/32)^2 + vo(vo/32) + ho

= -16(vo^2/32^2) + vo^2/32 + ho

=-vo/64 + vo^2/32 + ho

= vo/64 +ho

h= -b/2a is the zero value for -16t^2 + vot + ho

= the solution = the x intercept = the zero(s)