Question

Solve x2 - 3x = -8.

Answer 1

Do you want to complete the square again or do you want to do the quadratic formula to factor it?

Answer 2

i think its asking for the square these are the options



x equals quantity of 3 plus or minus I square root of 29 all over 2

x equals quantity of 3 plus or minus I square root of 23 all over 2

x equals quantity of negative 3 plus or minus I square root of 29 all over 2

x equals quantity of negative 3 plus or minus I square root of 23 all over 2

Answer 3

It's asking you to solve for x. You could do that by either using the quadratic formula or by completing the square. Up to you.

Answer 4

ill go with quadratic formula @IMStuck

Answer 5

It's in the form it needs to be in to complete the square but that doesn't mean you can't change it. Let's do the QF then!

Answer 6

In your polynomial, we will move the 8 over to the other side with the other terms, like this:\[x ^{2}-3x+8=0\]with a = 1, b = -3 and c = 8. And do you know the formula?

Answer 7

Uh nah i forgot :/ @IMStuck

Answer 8

Thats ok...I will post it for you, ok?

Answer 9

Okay @IMStuck

Answer 10

\[x=\frac{ -b \pm \sqrt{(b)^{2}-4ac} }{ 2a }\]Look familiar?

Answer 11

That -b out front is actually "the opposite of b". We have b as -3 so we will use the opposite of -3 and get 3 for our term out front, and here's the rest of it filled in:\[x=\frac{ 3\pm \sqrt{(-3)^{2}-4(1)(8)} }{ 2 }\]

Answer 12

Doing the math on that gives you:\[x=\frac{ 3\pm \sqrt{-23} }{ 2 }\]

Answer 13

And I am guessing you are familiar with how to deal with negatives under the radical sign in a square root?

Answer 14

no im not @IMStuck

Answer 15

you have to use the imaginary "i". Your answer will be\[x=\frac{ 3\pm i \sqrt{23} }{2 }\]

Answer 16

the second choice down in your options up above.

Answer 17

I don't understand how you could be expected to deal with imaginary numbers when you don't know how they work.

Answer 18

thank you @IMStuck