hi, i need to completing square on this:
x^2+2x-5=0
for this would i be correct if i got this:
(x+1)^2 -1 -5= (x+1)^2-6 ????
if this isn't correct where am i going wrong?
thanks!
if you are to complete the square then that generally implies you are to solve for x. completing the square is a type of factoring. when you factor it is to find solutions. if you need to graph the function then you would not take the square root and keep it in standard form.
standard form for graphing:
$\displaystyle f(x)=(x+1)^2-6$
general form:
$\displaystyle x^2+2x-5=0$
If this was the original problem, it should be $\displaystyle (x+1)^2- 6$
I would NOT say that "if you are to complete the square then that generally implies you are to solve for x." All it implies is that you are to complete the square. I also would not say "when you factor it is to find solutions". There may be many reasons to factor a polynomial.
general form:
$\displaystyle x^2+2x-5=0$
hi again, you find x i know i have to take away 1 from each side to get, x= square root 6 -1
im unsure what to do after this because two numbers times together to make this doesn't work because there isn't a square number to do this.
could you let me know how i could solvew this please?
cheers
We have
$\displaystyle x = \pm \sqrt{6} - 1$
When x is squared, there are two solutions. Sometimes they are the same one, sometimes they are complex, but there are two. In this case one x is
$\displaystyle \sqrt{6} - 1$
while the other is
$\displaystyle -\sqrt{6} - 1$