Question

361/9 a^2 = a^2 + 16

Show how you get 3 square root of 22/22 by solving for a

Answer 1

cross multiplying:
9a^4 + 144a^2 - 361 = 0
ley a^2 = A
9A^2 + 144A - 361 = 0
solve using quadratic formula
them a^2 = roots of this equatiuon

Answer 2

i don't understand what you mean by cross mulitiplying...
and how did you get 144?

Answer 3

rewriting:

361 a^2 + 16
---- = ---------
9 a^2 1

multiply top by bottom starting from 361 and bottom to top by 9 a^2 ( like a cross)

so 361 * 1 = 9a^2 * (a^2 + 16)

Answer 4

so 361 = 9a^2 * a ^2 + 9^a2 * 16
361 = 9 a^4 + 9*16 a^2
361 = 9a^4 + 144 a^2

Answer 5

and writing in standard form
9a^4 + 144 a^2 - 361 = 0

Answer 6

it's either 3square root of 22/22 or 12/square root of 352

Answer 7

is it this?

Answer 8

yes, but I want to see the work.

Answer 9

in any case
a^2 = - 144 +- sqrt((144^2 - 4*9*-361)
------------------------------
18
= -8 +- sqrt(20736 + 12996)
------------------
18
= -8 + 183.66 or -8 - 183.66
------ ------ - this is discounted as a^2 cannot be negative
18 18

a^2 = -8 + 10.2 = 2.2

a = + sqrt 2.2 or - sqrt 2.2
= 1.48 or -1.48

which is different from your answers
- of course i might be wrong!!

Answer 10

please clarify the left hand side of the equation is it
(361/9) time s a^2 OR 361 divided by 9a^2 ?

Answer 11

(361/9) times a^2

Answer 12

ah - thats different - it looked like my second option

Answer 13

u should have written it as ( 361 a^2) / 9 to avoid confusion
so now its a different story..

Answer 14

( 361 a^2) / 9 = a^2 + 16
( 361 a^2) / 9 - a^2 = 16
352 a^2 / 9 = 16
352 a^2 = 144
a = sqrt (144/352)
= 12 / sqrt352 or -12 / sqrt352

Answer 15

at last!!

Answer 16

THANKS SO MUCH !!

Answer 17

lol - yw

Answer 18

sorry for wasting your precious time to help me. you're the best

Answer 19

thats ok