Question

Use "completing the square" to find the zeros of the polynomial.

=2x squared + 6x + 5 = 0

Answer 1

correction of problem. Should be:
-2x squared + 6x + 5 = 0
Sorry about that!

Thanks for your help!

Answer 2

well, this one is different anyway

-2 x^2 + 6 x + 5 = y find zeros

x^2 - 3 y - 2.5 - -y/2

x^2 - 3 y = -y/2 + 5/2

x^2 -3 y + 9/4 = -2 y/4 + 10 y/4 + 9/4

(x- 3/2)^2 = -1/2 (y -19/2)
when y = 0
(x-3/2)^2 = 19/4

so
x = 3/2 +/- 1/2 sqrt 19

check with quad eqn
x = [ -6 +/- sqrt (36 +40) ]/-4

= 3/2 +/- sqrt (76)/4

= 3/2 +/- 2 sqrt 19/4

= 3/2 +/- (1/2) sqrt 19 sure enough