Question

2x^2+5x-8=0

Answer 1

to solve this , as the function will not factor you can either complete the square or use the quadratic formula
(Completing the square is a similar process to finding the vertex)

Answer 2

use the quadratic formula

Answer 3

ok let me try it.

Answer 4

ax^2 + bx + c = 0
A=2
B=5
C= -8
put the values in formula and u get ur result