Answer: 154
Step-by-step explanation:
[tex]a_1=4,\ d=6\quad \rightarrow \quad a_n=4+6(n-1)\quad \rightarrow \quad a_n=6n-2\\\\\\\sum^7_{n=1}6n-2\\\\\\a_1=4\\a_7=40\\\\\\S_n=\dfrac{a_1+a_7}{2}\cdot n\qquad =\dfrac{4+40}{2}\cdot 7\qquad =22\cdot 7\qquad =\large\boxed{154}[/tex]
