Question 1022804
Solve by completing the square:
y^2 + 5y - 2 = 0
y^2 + 5y + __ = 2
Find the value that completes the square; (5/2)^2 = 6.25
y^2 + 5y + 6.25 = 2 + 6.25
y^2 + 5y + 6.25 = 8.25
factors to
(y + 2.5)(y + 2.5) = 8.25
y + 2.5) = +/-{{{sqrt(8.25)}}}
y = -2.5 + {{{sqrt(8.25)}}}
and
y = -2.5 - {{{sqrt(8.25)}}}
:
Solve by using the Quadratic Formula
2x^2 - 4x - 9 = 0 
{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}
a=2; b=-4; c=-9
{{{x = (-(-4) +- sqrt(-4^2-4*2*-9 ))/(2*2) }}}
{{{x = (4 +- sqrt(16+72 ))/4 }}}
{{{x = (4 +- sqrt(88))/4 }}}
{{{x = (4 + 9.38)/4 }}}
x = 3.345
and
{{{x = (4 - 9.38)/4 }}}
x = -1.345