What do you think? What is the answer for this ?

For what values of the variable x is the expression square root of 7x+14+ square root of 7-x a real number?

Ithink i know it but i want to be sure so can you me out ?

Given: jk ||lm prove: _2 = 27 statement justification 1. jk ||lm 1. given 2.26 = 27 3.22 = 26 2. 3. 4. _2 = 27 4. corresponding angles theorem transitive property of equality vertical angles theorem substitution property of equality