Algebra Answers

Tamil has $600 in his bank account & Niydiyah has $500 in hers. Each Friday Tamil withdraws $15 and Niydiyah withdraws $12. Will their bank balances ever be equal? if they are equal how many weeks will it take? If they are not equal, whats the smallest difference?

What is the equivelant expression of 2(x+4)

Beka and melanie have 28 coins that are nickels and dimes. if the value of the coins is $1.95 how many nickels do they have?

Suppose m(n)=1/6n^2.
(a) Find a formula for y=m(n+8)−7 in terms of the variable n.
y=m(n+8)−7= __________
I have tried numerous things. I did not understand how to complete this

if the sum of first n even natural numbers is equal to k times the sum of first n odd natural numbers then k=?
(a)1/n (b) n-1/n (c) n+1/2n (d) n+1/n

Let Sn denote the sum of n terms of an AP whose first term is a .If the common difference d is given by d= sn- k sn-1+sn-2 then k= ?
(a) 1 (b) 2 (c) 3 (d) None

in the AP whose common difference is non zero the sum of first 3n terms is equal to the sum of next n terms, then the sum of the first 2n terms to the next 2n terms is
(a) 1/5 (b) 2/3 (c) 3/4 (d) none

504 000 mg is what in kilograms and grams?

I am studying for my mid terms them this question popped up;
What are the sums of the following pairs of numbers?
a) 45 and 67 b) 2366 and 734 c) 399 and 60987 d) 908.34 and 456.88
I just got so confused! Can someone please give me the answers or at least help me? I'm begging! (I'm only in 7th grade btw) :p

(12a5−6a−10a3)−(10a−2a5−14a4)