Question

Find the zeros of this quadratic.
2x^2 - 8 = 0

Answer 1

\[2x ^{2}-8=0\]

Answer 2

would it be x=4, 9

Answer 3

@jim_thompson5910 sorry for troubling you so much

Answer 4

2x^2 - 8 = 0

2x^2 = 8

x^2 = 8/2

x^2 = 4

x = ??? or x = ???

Answer 5

also you can check your possible answers,

checking x = 9 as a possible answer

2x^2 - 8 = 0

2(9)^2 - 8 = 0 ... plug in x = 9

2(81) - 8 = 0

162 - 8 = 0

154 = 0 ... which is FALSE

So x = 9 is NOT a solution

Answer 6

oops i meant to put x= 4, 0

Answer 7

ok check x = 0

2x^2 - 8 = 0

2(0)^2 - 8 = 0 ... plug in x = 0

2(0) - 8 = 0

0 - 8 = 0

-8= 0 ... which is FALSE

So x = 0 is NOT a solution

Answer 8

see how I'm checking the answers?

Answer 9

yeah thanks for all your help!

Answer 10

np

Answer 11

wait, so how do i solve for the zeros. i got 4, 0 but those aren't true

Answer 12

no I just showed you why it's not true

I just showed how x = 0 wasn't a solution

Answer 13

also I had steps leading up to this equation

x^2 = 4

so if x^2 = 4, then x is equal to what two values?

Answer 14

It's all above in separate posts

Answer 15

ohh +- 2

Answer 16

better

Answer 17

to check each solution, just plug it in for each x and evaluate

so you should be able to plug in x = 2 in for each x and evaluate and you will get zero if you do everything correctly

that would confirm that x = 2 is a true solution to 2x^2 - 8 = 0

Answer 18

I recommend doing this for any equation you solve because not all possible solutions are actual solutions