Complete the Square:
\[2x^2+8x-7=-2\]
break it down to a simply problem
then do the pemdas stage
would you start by adding seven to both sides?
\[2x^2+8x-7=-2\]
You could do that, but I don't see how that step would help you. This is an equation, namely, a quadratic equation, and you'll want all terms on the left side.
If you want to move the -2, fine. Add 2 to both sides of this equation.
so 2x^2+8x-5=0
Yes. Now make things easier for yourself by factoring 2 out of the first 2 terms. Use parentheses. Leave the -5 alone.
2(x^2+4x)-5=0?
Yes, very good. Now focus on completing the square of x^2+4x.
1) Take half of the coefficient of x (which is 4). 2) Square your result. 3) Add this result to the first 2 terms, and then subtract this result from the left 3 terms. Show your work.
I'm confused. what terms do i have to add or subtract it from? i get the whole (b/2)^2 , I'm not sure on where to add this too
b is 4. Half of b is 2. Square this result. It's 4. Add this 4, and then subtract this 4: x^2+4x +4 -4
x^2+4x+4 is the square of what binomial? Write your answer in the form ( )^2-4.
(x+2)^2-4
Yes. Now, let's put this problem back together: 2x^2+8x-5=0 2(x^2+4x)-5 = 0 Replace (x^2+4x) with ( (x+2)^2 -4 ). Show your work.
so it'd be 2(x+2)^2-9=0?
Here's what I would do: 2 [(x^2+4x+4 - 4)] - 5 = 0 2 [ (x+2)^2 - 4] - 5 = 0 2(x+2)^2 - 8 -5 = 0 Please go thru this and decide whether you can accept it or not.
okay i think i got it. thank you
My pleasure! Bye for now.
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