Step-by-step explanation:
using
The quadratic general formula
which is
r= -b±√(b²-4ac)
---------------
2a
b= coefficient of r=3
a = coefficient of r²=2
c= constant or number without any variable=-10
r= -3±√(3²-(4×2×-10)
-----------------------
2×2
r=-3±√(9-(-80)
----------------
4
r= -3±√(9+80)
------------
4
