Question

what value would you add to each side to complete square
x^2+18x=-8

Answer 1

what value do you think we should add?

Answer 2

I am not sure 9

Answer 3

x^2+18x = x^2 + 2*9*x +0
here's the formula: a^2 + 2ab + b^2 = (a+b)^2
so, you can see a=x, b=9. you are missing b^2, to complete square you'll need b^2, which is 9^2=81
so add 81 to each side.

Answer 4

Is That it

Answer 5

try it, then you tell me the result.

Answer 6

9 is a good number to use, but it is naked the way it is; square it and were good :)

Answer 7

I am really confused should I square the complete equation?

Answer 8

you can't square the whole equation. you should end up with something like this
(x+a)^2+b=0
a and be can be positive or negative.

Answer 9

except for some cases where you can just put them together nicely, of course.

Answer 10

i had a similar problem and don't understand how to do it and how they came up with the answer it was x^2+16x=-7 the answer was 64

Answer 11

try to put the left side into this form a^2 + 2ab + b^2. add something to make b^2, remember, you add something, you have to subtract it

Answer 12

a=1 b=18 c=-8

Answer 13

I know that I am having problems solving this because I can't find an example to use

Answer 14

b^2 = (2ab/2a) *b

Answer 15

ok, I'll do you this one example.
x^2+16x=-7
x^2+16x+7=0
x^2+2*x*8+7=0

compare this to
a^2 + 2*a*b + b^2=(a+b)^2

you can see clearly that
a=x
b=8

so if b=8, b^2=64, you need to add 64, but you add 64, you need to subtract 64

then equation becomes
x^2 + 2*x*8 + 64 - 64 + 7=0
(a+8)^2 + (-64+7) = 0
(a+8)^2 - 57 = 0

there's the answer

Answer 16

18/2(1) = 9*9 = 81

Answer 17

(a+9)^2-73=0
So I would add 81 to both sides

Answer 18

??? I dont get it.

Answer 19

x^2+18x=-8
x^2+2*x*9+81-81+8=0
(a+9)^2+(-81+8)=0
(a+9)^2-73=0
I would add 81 to both sides

Answer 20

exactly. that's right

Answer 21

Thank you now I have an example to go by

Answer 22

anytime

Answer 23

5x^2-3=0 no solution is that correct?

Answer 24

thank you got to go let me know if that is right

Answer 25

you mean to complete square, no, but there are solutions, add 3 to both sides, then divide both sides by 5, you'll get x^2=3/5=(sqrt(3/5))^2=(-sqrt(3/5))^2
so x=sqrt(3/5) or x=-sqrt(3/5)

Answer 26

thanks i figured it out square root property

Answer 27

ah that's good, good luck with ur maths