$\huge \int x^{6}\sinh\!\left(x^{7}+6\right) \, \d x $ $\huge \begin{align} \let u &=x^7+6\\ \let \d u &= 7x^6 \\ \\ \int x^{6}\sinh\!\left(x^{7}+6\right) \, \d x &= \frac{1}{7}\int\sinh(u)\d u \\ &=\frac{1}{7}\cosh(u)+C \\ &=\frac{1}{7}\cosh(x^7+6)+C \\ \end{align}$