Question

solve for x.
y=x^2+2x-1

Answer 1

Gonna have to complete the square.

Answer 2

good idea

Answer 3

Or plug y into the quadratic formula.. But I prefer the former.

Answer 4

me too. especially since you have 2x

Answer 5

yep

Answer 6

x^2+2x-(1 + y) = 0

Answer 7

ew.. vijay's doin in the other way.

Answer 8

\(y = x^2 + 2x + 0 - 1\)
\[\implies y = x^2 + 2x + (1 - 1) - 1\]\[\implies y = x^2 + 2x + 1 - 2\]\[\implies y = (x+1)^2 - 2\]\[\implies y + 2 = (x+1)^2\]\[\implies x + 1 = \sqrt{y+2}\]\[\implies x = \sqrt{y+2} - 1\]

Answer 9

\[x^2+2x-1=y\]
\[x^2+2x=y+1\]
\[(x+1)^2=y+1+1\]
\[(x+1)^2=y+2\]
\[x+1=\pm\sqrt{y+2}\]
\[x=-1\pm\sqrt{y+2}\]

Answer 10

Oh, forgot the +-

Answer 11

that's ok i put it in

Answer 12

Yep