Question

S20= 100 and d=-2 then a=?

Answer 1

Answer:

Step-by-step explanation:

Answer 2

$\huge{\mathfrak{\underline {\underline{</p><p><strong>Answer:</strong></p><p>}}}}$

Given :-

Common difference (d) = -2

S 20 = 100

To Find :-

First term (a) = ?

Solution :-

Using formula :-

$\huge{\boxed{\orange{ an \:=\:a \:+\:(n - 1) d}}}$

Putting values

100 = a + (20 - 1) -2

100 = a + 19( -2 )

100 = a - 38

100 + 38 = a

138 = a

$\huge{\boxed {\red{138}}}$