Answer:
Step-by-step explanation:
18. x can also become the negative integral square root of 9, which is -3.
[tex]\sqrt{9}=-3,3[/tex]
19.
[tex]2x-x=x\\2x=2x\\[/tex]
Here, as x is a variable, it can take any values. As its co-efficient (2) is same both in the RHS and LHS... the LHS=RHS, for any (Real) values of x
