Question 417879
{{{2b^2 +9=0}}}

{{{2b^2=-9}}}

{{{b^2=-9/2}}}

{{{b^2=-4.5}}}

{{{b}}}=+-{{{sqrt(-4.5)}}}

{{{b}}}=+-{{{sqrt(-1*4.5)}}}

{{{b}}}=+-{{{i*sqrt(4.5))}}}

{{{b}}}=+-{{{(2.12)i}}}



{{{b1=(2.12)i}}}

{{{b1=-(2.12)i}}}

check:

{{{2b^2 +9=0}}}

{{{2(2.12i)^2 +9=0}}}

{{{2(4.4944(-1)) +9=0}}}

{{{-8.9888 +9=0}}}.....round {{{-8.9888=9}}}

{{{-9 +9=0}}}