SOLUTION: Hello. I am having an issue solving this problem and I look to you for help. My problem is: {{{6sqrt(12)}}}-{{{8sqrt(50)}}}+{{{9sqrt(72)}}}. By using prime factorization, I know

Algebra ->  Radicals -> SOLUTION: Hello. I am having an issue solving this problem and I look to you for help. My problem is: {{{6sqrt(12)}}}-{{{8sqrt(50)}}}+{{{9sqrt(72)}}}. By using prime factorization, I know      Log On


   

Question 993742: Hello. I am having an issue solving this problem and I look to you for help. My problem is:
6sqrt%2812%29-8sqrt%2850%29+9sqrt%2872%29. By using prime factorization, I know that 12 = 2^2*3
50 = 5^2*2
72 = 3^2*2^3
Now, I plug these terms back in and I get:
6%2A2sqrt%283%29-8%2A5sqrt%282%29+9%2A3%2A2sqrt%282%29 If I continue, I get:
12sqrt%283%29-40sqrt%282%29+54sqrt%282%29
The answer key shows that the answer should be
57sqrt%283%29-40sqrt%282%29 Can you see where I went wrong? I'm not coming up with the right answer.

Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
i think the answer key is wrong.

here's a quick check using my calculator.

the original equation is:

6*sqrt(12) - 8*sqrt(50) + 9*sqrt(72)

the calculator says that the value of that is equal to 40.58359956

the book answers value is equal to 57*sqrt(3) - 40*sqrt()2) which is equal to 42.15835354.

the answers are not the same so the book answer has to be wrong.

your answer is equal to 12 * sqrt(3)-40 * sqrt(2)+54 * sqrt(2) which is equal to 40.58359956.

since this is the same as you get with the original equation, then it must be right.

i did the analysis and came up with the same answer that you did.

you could simplify it further to get 12 * sqrt(3) + 14 * sqrt(2).

using your calculator to do a quick check is a good way to find out if you're right or wrong.

you just match the answers using the original equation and the revised equation.

if they match, you did good.

if they don't, you didn't.

most calculators have a sqrt key.

if they don't, then you can use the exponential form instead.

for example:

6 * sqrt(12) can also be entered as 6 * (12)^(1/2).