Question

t3=18, t6=486 find s5​

Answer 1

Answer:

$\huge{\boxed{\boxed{\sf{S5=65}}}}$

Step-by-step explanation:

$\huge{\boxed{\boxed{\underline{\sf{SOLUTION-}}}}}$

>> T3 = 18 (Given)

>> T6 = 486 (Given)

>>We have to find sum of 5th term that is S5 = ?

>>According to the question:

$(t3) \\ = )a + 2d = 18 - - - - - (1) \\ (t6) \\ = )a + 5d = 486 - - - - - (2) \\ subtracting \: (1) \: from \: (2) we \: get \\ = ) 3d = 468 \\ = ) d = \frac{468}{3} \\ =)d = 156 \\ putting \: value \: of \: d \: in \: (1) \\ so \: we \: get \: first \: term \\ = )a + 2 \times 156 = 18 \\ = ) a +312 = 18 \\ = ) a = 18 - 312 \\ = )a = - 294 \\a = - 294 \: \\ \: d = 156 \\</u><u>a</u><u>g</u><u>a</u><u>i</u><u>n</u><u>\</u><u>\</u><u>t5 = a5= a + 4d = \\ = ) - 294 + 4 \times 156 \\ = ) - 294 + 624 \\ = )330 \\ we \: have \: to \: find \: sum \: of \: s5 \\ s5 = \frac{n}{2} (a + an) \\ s5 = \frac{5}{2} ( - 294 + 330) \\ s5 = \frac{5}{2} \times (26) \\ s5 = 5 \times 13 \\ s5 = 65$

$\huge{\boxed{\boxed{\sf{S5=65}}}}$

Answer 2

EXPLAINED CLEARLY IN THE PICTURE

HOPE IT HELPS.........

PLS MARK AS BRAINLIEST