Chapter 5, Problem 39RE

Properties of integrals Suppose that ${\displaystyle {\int }_1^{4}f(x)dx=6}$, and ${\displaystyle {\int }_1^{4}g(x)dx=4}$, and ${\displaystyle {\int }_3^{4}f(x)dx=2}$. Evaluate the following integrals or state that there is not enough information.

39. ${\displaystyle {\int }_1^{4}3f(x)dx}$