## anonymous 5 years ago 8z^2-64 when factored out does this equal 8(z-8)(z+8)

1. anonymous

8 ( z^2 - 8 )

2. dumbcow

when you factor out the 8 you need to divide the 64 by 8 as well

3. amistre64

its just a matter of taking the time to multiply it all together again; you can do it :)

4. anonymous

so when i multiply it all back out it gives me my 8z^2-64 ohhhh ok lol im just trying to get other peoples opinions o my answers and check my answers for an assighnment i have

5. amistre64

(2z sqrt(2) +8) (2z sqrt(2) -8) is what i get

6. amistre64

8.8.8 > 64

7. anonymous

we arent supposed to use the quadratic equation we dont learn that til junior year

8. amistre64

this factors to a difference of squares

9. amistre64

your original conclusion there is wrong

10. anonymous

but when i multiply it all back it gives me the original equation

11. anonymous

?

12. anonymous

what would it equal then cause its confusing me

13. anonymous

$= 8 ( z^2 -8 )$$= 8 ( z-\sqrt{8})(z+\sqrt{8})$

14. anonymous

thats it , noting else

15. anonymous

or you could write it as $8 ( z-2\sqrt{2})(z+2\sqrt{2})$ as $\sqrt{8} = \sqrt{4 \times 2} = \sqrt{4} \times \sqrt{2} = 2\sqrt{2}$

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