Cho \(\int\limits_{ - 3}^0 {f\left( x \right)dx} = - 4\) và \(\int\limits_{ - 3}^0 {g\left( x \right)dx} = - 3\). a) \(\int\limits_0^{ - 3} {f\left( x \right)dx} = - 4\). b) \(\int\limits_{ - 3}^0 { - 3f\left( x \right)dx} = 12\). c) \(\int\limits_{ - 3}^0 {\left[ {f\left( x \right) + g\left( x \right)} \right]dx} = - 7\). d) \(\int\limits_{ - 3}^0 {\left[ {f\left( x \right) + 3x} \right]dx} = - 10\).