Question

Best answer will be marked brainliest....​

Answer 1

Answer:

d=-4

a(first term)=56

Step-by-step explanation:

take the sum of first 12 terms

n/2(2a+(n-1)d)=sum

12/2(2a+11d)=348

6(2a+11d)=348

2a+11d=348/6=58       - 1st eq

take the sum of first 10 terms

by using formula

10/2(2a+9d)=330

2a+9d=330/5

2a+9d=66                    -2nd eq

eq1-eq2=

2a+11d=58

-[2a+9d]=-66

2d=-8

d [common difference]=-4

putting d value in eq 2

2a+9[-4]=66

2a=66+36=102

a=102/2=56

[a=56]