Can someone help explain radical equations?

Question

primeralph · Answer

like roots ?

anonymous · Answer

For example 
	 Sqrt (3x + 46)  = x + 6

anonymous · Answer

i know how to solve it and get solutions

primeralph · Answer

So what do you need?

zale101 · Answer

I don't know what you're trying to ask exactly, but this might help u out :) http://www.purplemath.com/modules/solverad.htm

jdoe0001 · Answer

http://www.mathsisfun.com/definitions/rational-expression.html

anonymous · Answer

the solutions are 10 and 1 but 10 is extranneous, right?

anonymous · Answer

Sqrt (3x + 46) = x + 6
square both sides: 3x + 46 = (x+6)^2
Expand binomial: 3x+46 = x^2 + 12x + 36
Simplify: 3x = x^2 +12x-10
             0 = x^2 + 9x - 10
             0 = (x+10)(x-1)
              x = -10, 1

anonymous · Answer

right?

anonymous · Answer

hello?

anonymous · Answer

@primeralph

primeralph · Answer

Yeah.

anonymous · Answer

so why isnt -10 right?

anonymous · Answer

sqrt (16) = -10 + 6
+/- 4 = -4

primeralph · Answer

- 10 is also right

anonymous · Answer

not according to the answer key

primeralph · Answer

Well maybe they wanted only one answer.

anonymous · Answer

Incorrect
	(3x + 46)
= x + 6
3x + 46 = x2 + 12x + 36
0 = x2 + 9x – 10
0 = (x – 1)(x + 10)
x = -10, 1
When -10 is substituted into the original equation, it returns a false statement. Therefore, x = 1.

anonymous · Answer

thats what the answers say

primeralph · Answer

It returns a false statement because the standard from of sqrt is positive unless specified as +/-sqrt

anonymous · Answer

so the sqrt of 25 is 5 unless specified?

primeralph · Answer

Generally, Yes.

primeralph · Answer

Medal?

anonymous · Answer

sorry forgot