# alg2\trig

posted by .

if a3= 17 & a8=37 are terms in annarithmetic sequece, fina a1 & d. the answer is a1=9 & d=4 but i don't understand how they got the answer, please help!

• alg2\trig -

term(3) = a + 2d (by definition)
= 17
term(8) = a + 7d = 37

a+7d = 37
a+2d = 17
subtract them
5d = 20
d = 4
sub into a + 2d=17
a + 8 = 17
d = 9

## Similar Questions

2. ### algebra

the equation is : - (2x + 3)-(4 + x). Using the distributive property, my friend got the answer -7 - 3x. I have been fiddling with this problem for 3 hours and don't understand how he got this answer. Can someone please thoroughly …

Change each decimal to a fraction in lowest terms. 1) 0.4242.... Answer: 14/33 2)0.58 Answer: 29/50 3)0.14 (Repeating sign over both numbers) Answer: 14/99 Write each expression in simplest form. ( means that it is inside a square …

Write each decimal as a fraction in lowest terms. 1. 0.111... Answer: 1/9 2. 0.02 Answer: 1/50 3. 0.7272... Answer: 8/11 4. 0.012012... Answer: 4/333 ?

6. ### alg2/trig

I got this question wrong on my test, and I have to correct it :/ How many permutations are there of all the letters in the word "TEXAS" ?
7. ### trig

Write the expression and evaluate. There is only one answer whIch should match the range of the inverse trig function. Sec^-1(-2) I got 2pi/3 could someone tell me if that is right?
8. ### chemistry

1) Starting with 75.00 g of 1-propanol and 75.00 g of PCl 3. Calculate the theoretical yield of 1-chloropropane. 3CH3CH2CH2OH + PCl 3 --> 3CH3CH2CH2Cl + H3PO3 Answer in terms of grams. the answer that i got is 98.12, is this right …