Question

Solve:

(u + 3)(u - 3) = 8u

Answer 1

expand the brackets first and then bring the 8u from the right hand side to the left and then factor.

Answer 2

and solve.

Answer 3

what do you mean by expanding the brackets?

Answer 4

do you know the foil method?

Answer 5

yes

Answer 6

use that.

Answer 7

ok. Then i get u^2-9=8u

Answer 8

yep. now bring the 8u to the left hand side.

Answer 9

So now I have u^2-8u-9=0

Answer 10

ok, now factorize again and solve.

Answer 11

ok

Answer 12

so after i factorize, i get (u-1)(u+9)=0

Answer 13

yes.

Answer 14

now solve to get u.

Answer 15

then the values of u would be -1 and 9, right?

Answer 16

nope.
u-1=0 u+9=0
now solve.

Answer 17

my fault, 1 and -9. got the signs mixed up

Answer 18

yes, that's correct.

Answer 19

ok. thanks!

Answer 20

no problem, medal thanks! lol