Answer:
145/2
Step-by-step explanation:
d=[2x+1-x] = [5x+1 -(2x+1)]
x+1=3x
x-3x=-1
-2x=-1
x=1/2
therefore first term is 1/2
second term is 2(1/2)+1= 2
common difference d is 2-1/2=3/2
sum of first n terms is n/2 [2a+(n-1)d] where n=10
sum of first 10 terms= 10/2[2×1/2+(10-1)3/2]
=5[1+(9)3/2] =5[1+27/2] = 5[29/2] =145/2
