SOLUTION: Solve the equation. (Enter your answers as a comma-separated list. If there is no solution, enter NO SOLUTION.) (3)(sqrt 4x &#8722; 7) + 2 = (sqrt 9 &#8722; x)= 17 <img src

Algebra ->  Radicals -> SOLUTION: Solve the equation. (Enter your answers as a comma-separated list. If there is no solution, enter NO SOLUTION.) (3)(sqrt 4x &#8722; 7) + 2 = (sqrt 9 &#8722; x)= 17 <img src      Log On


   



Question 906578: Solve the equation. (Enter your answers as a comma-separated list. If there is no solution, enter NO SOLUTION.)

(3)(sqrt 4x − 7) + 2 = (sqrt 9 − x)= 17

The answers I got: (8,851/100), (97/10), and (-19/4) all came up incorrect on my homework.

Found 2 solutions by Theo, Edwin McCravy:
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
your solution is x = 8 and x = 8.51

the steps taken are shown in the following pictures.

$$$

$$$

if you have any questions with any of the steps, let me know.








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Answer by Edwin McCravy(20055) About Me  (Show Source):
You can put this solution on YOUR website!
3sqrt%284x-7%29+%2B+2sqrt%289-x%29=+17
Let one of the square roots equal to a letter

Let sqrt%289-x%29=A

Then we have:

3sqrt%284x-7%29+%2B+2A=+17

Isolate the remaining radical term on the left

3sqrt%284x-7%29+=+17-2A

Square both sides:

%283sqrt%284x-7%29%29%5E2+=+%2817-2A%29%5E2

9%284x-7%29=%2817-2A%29%2817-2A%29

36x-63=289-34A-34A%2B4A%5E2

36x-63=289-68A%2B4A%5E2

36x=352-68A%2B4A%5E2

Now since  A=sqrt%289-x%29, A%5E2=9-x

36x=352-68sqrt%289-x%29%2B4%289-x%29

36x=352-68sqrt%289-x%29%2B36-4x

36x=388-68sqrt%289-x%29-4x

Isolate the square root term:

68sqrt%289-x%29=388-40x

Divide through by 4

17sqrt%289-x%29=97-10x

Square both sides:

%2817sqrt%289-x%29%29%5E2=%2897-10x%29%5E2

289%289-x%29=%2897-10x%29%2897-10x%29

2601-289x=9409-970x-970x%2B100x%5E2

2601-289x=9409-1940x%2B100x%5E2

0=6808-1651x%2B100x%5E2

100x%5E2-1651x%2B6808=0

That may factor, but it would take longer to
factor it than to use the quadratic formula,
so I'll just use the quadratic formula:

 x+=+%28-b+%2B-+sqrt%28+b%5E2-4ac+%29%29%2F%282a%29+
 
 

 x+=+%281651+%2B-+sqrt%282601%29+%29%29%2F200+

 x+=+%281651+%2B-+51+%29%2F200+ 

Using the +

 x+=+%281651+%2B+51+%29%2F200+

 x+=+1702%2F200+ 

 x+=+851%2F100

Using the -

 x+=+%281651+-+51+%29%2F200+

 x+=+1600%2F200+ 

 x+=+8

So the solutions are 851%2F100 and 8

But we must check to see if they are really solutions:

checking 851%2F100

3sqrt%284x-7%29+%2B+2sqrt%289-x%29=+17
3sqrt%284%28851%2F100%29-7%29+%2B+2sqrt%289-851%2F100%29=+17
3sqrt%28851%2F25-7%29+%2B+2sqrt%289-851%2F100%29=+17
3sqrt%28851%2F25-175%2F25%29+%2B+2sqrt%28900%2F100-851%2F100%29=+17
3sqrt%28676%2F25%29+%2B+2sqrt%2849%2F100%29=+17
3%2826%2F5%29%2B2%287%2F10%29=17
78%2F5%2B14%2F10=17
156%2F10%2B14%2F10=17
170%2F10=17
17=17

checking 8

3sqrt%284x-7%29+%2B+2sqrt%289-x%29=+17

3sqrt%284%2A8-7%29+%2B+2sqrt%289-8%29=+17

3sqrt%2832-7%29%2B2sqrt%281%29=17

3sqrt%2825%29%2B2%281%29=17

3%2A5%2B2=17

15%2B2-17
17=17

They both check.

Edwin




Edwin