Grade 11 Sequences help pleasee!

Question

pottersheep · Answer

p-4, 8p + 3 , 10p - 5 are the 4th, 6th and 8th terms of an arithmetic sequence. Find:

a) 1st term of the sequence
b) common difference

anonymous · Answer

solve the equation 
p-4=a+3d
8p+3=a+5d
10p-5=a+7d

a is the first term and d is the common difference

pottersheep · Answer

I do do those things but that answer for a) never matches the right answer in my book. 

The answer for part a) is 14.

pottersheep · Answer

I get weird fraction numbers...

anonymous · Answer

p=-3, d=-7, a=14, what is your answer?

pottersheep · Answer

for d I got 7(p+1) /2
a I got 19p + 29/2

anonymous · Answer

there are three equations, plug a and d in them, and then you work out p

pottersheep · Answer

so then to find p I did

p - 4 (which is term 4)  = a + 3d
p - 4 = (19 + 29) /2  + 3(7p+7)/2

2p-8 = 19p + 29 + 21p + 21
2p - 8 = 40 p + 50.............

-38 p = 58
:(

anonymous · Answer

hey i found the error! a=- (19p+29)/2

pottersheep · Answer

:O....

pottersheep · Answer

Thank you !! I wish I could give you more medals !! I spent so much time on thiss ahhhhh at least it was a rather minor error........meh THANKS!!

anonymous · Answer

haha!