Cho hàm số \[y = f( x )\]liên tục trên \[[ {a;b} ]. Mệnh đề nào đúng?

\[\int\limits_a^b {f\left( x \right){\rm{d}}x} = \int\limits_b^a {f\left( x \right){\rm{d}}x} \].

\[\int\limits_a^b {f\left( x \right){\rm{d}}x} = - \int\limits_b^a {f\left( x \right){\rm{d}}x} \].

\[\int\limits_a^b {f\left( x \right){\rm{d}}x = 2\int\limits_a^b {f\left( x \right){\rm{d}}\left( {2x} \right)} } \].

\[\int\limits_a^b {2024f\left( x \right){\rm{d}}x = 0} .\]