Answer: 925
Step-by-step explanation:
First, we need to find the first term (a₁) and the last term (a₂₅):
[tex]a_n=3n-2\\\\a_1=3(1)-2\\.\quad =3-2\\.\quad =1\\\\a_{25}=3(25)-2\\.\quad = 75-2\\.\quad = 73[/tex]
Now we can input the information above into the Sum formula:
[tex]S_n=\dfrac{a_1+a_n}{2}\times n\\\\S_{25}=\dfrac{a_1+a_{25}}{2}\time 25\\\\.\quad =\dfrac{1+73}{2}\times 25\\\\.\quad =\dfrac{74}{2}\times 25\\\\.\quad =37\times 25\\\\.\quad =925[/tex]
