Question 808600
In an arithmetic sequence the seventh term is 9 times the first and the fourth
term is less than the fifth term by 4: Find the first term and the common
difference.

tn = a+(n-1)d

t7=a+6d

a+6d = 9a

8a=6d
4a=3d

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T4 = a+3d
t5=a+4d



a+4d-(a+3d)=4
a+4d-a-3d=4
d=4

4a=3d
d=4
4a=12
a=3

a=3, d=4