Answer:
Step-by-step explanation:
t5 = a + (5-1)d
t5 = a + 4d
40 = a + 4d
t3 = a + 2*d
t7 = a + 2d + 28 = a + 6d
Start with the seventh term which has 2 equal answers
a + 2d + 28 = a + 6d Subtract a from both sides
2d + 28 = 6d Subtract 2d from both sides
28 = 4d Divide by 4
28/4 = d
d = 7
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t5 = a + 4d = 40
a + 4*7 = 40
a = 40 - 28
a = 12
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First term is 12
10th term is
t10 = 12 + (10 - 1)*7
t10 = 12 + 9*7
t10 = 75
Interesting question. Thanks for posting
