Question

find the common difference of the AP whose sum of first four terms is 40 and that of fourteen terms is 280​

Answer 1

Answer:

d = 56

Step-by-step explanation:

s4 = 4/2( 2a+3d)=40

s14=14/2(7a+13d)=280

4a+3d=40

14a+13d=280

solve them

d=56