**2. In each part, determine whether the equation is linear in x and y.**

The equation is **linear** in x and y.

The equation is **not linear** x and y due to the terms and .

The equation is **linear** in and x and y.

The equation is **not linear** in x and y due to the term cosx.

(e) xy = 1

The equation xy = 1 is **not linear** in x and y due to the term xy.

(f ) y + 7 = x

The equation y + 7 = x is **linear** in x and y.