Which undefined term can contain parallel lines

(9x-5) - (x+12) what’s the answer and also explain how to do it i need it for a test tomorrow

What is the area of a triangle with vertices at (-3 3) (-3,2) and (1,2)?

This is a rational expression because the denominator contains a variable. this is a polynomial with 3 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 4 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 4 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 3 terms. this is a rational expression because the denominator contains a variable. this is a polynomial with 5 terms.