Question

in an AP ,a= 4,n=6,Sn=84 find d

Answer 1

$sn = \frac{n}{2} (2a + (n - 1)d) \\ 84 = 3(8 + 5d) \\ 5d = 20 \\ d = 4$

Answer 2

This is the required answer. Mark it as brainlest.