Posted by **Felicia** on Tuesday, October 30, 2012 at 5:13pm.

square root ( 2x+1) +x=7

- algebra -
**Steve**, Tuesday, October 30, 2012 at 5:18pm
√(2x+1) + x = 7

√(2x+1) = 7-x

2x+1 = 49 - 14x + x^2

x^2 - 16x + 48 = 0

(x-12)(x-4) = 0

x = 4 or 12

check:

√(2*4+1)+4 = √9 + 4 = 3+4 = 7

√(2*12+1)+12 = √25 + 12 = 5+12 = 17 BOO!

Why? Because this is true only if we take the -√: -5+12 = 7, but that's not the original equation. Squaring both sides allowed for using + or - √.

## Answer This Question

## Related Questions

- Algebra - Rationalize each expression by building perfect nth root factors for ...
- Algebra - Use the quadratic formula to solve the equation. Give exact answers: ...
- algebra - Which shows the expressions in the order they would appear on a number...
- Math simplifying mixed radicals - Please help me simplify these following mixed ...
- algebra 2 - Not sure if either one of these answer are correct to simplify the ...
- algebra - 1.)correct 2.)wrong---> the first term is wrong 4(3a^2)^2 = 36a^4 3...
- Math ~CHECK MY ANSWER~ - 1) Which of these is a rational number? a. Pi b. Square...
- Pre- Algebra - State if each number is Rational,Irrational,or not a real number...
- Algebra check? - Sorry the first post formatted weirdly. 1. 3i - 10 --------- 8i...
- College Algebra - I need some help with a handful of questions. I need to see ...

More Related Questions