# Determing whether an equation is linear

#### delgeezee

##### New member
Linear equations do not have roots of variables.
So why are a) and f) linear equations?

#### Jameson

I agree that if (a) contains $-\sqrt{2x_3}$ then it isn't a linear equation. Perhaps it is a typo and it should be $-\sqrt{2} \hspace{1 mm} x_3$?