What i 2x2=?? i don't know please help me:(

Idon't get undoing if its pass adding and subtracting so can someone ? x-2 over 5 = 18

Gia opened two savings accounts at two different banks. one account earns an annual 3.4% simple interest, and the other earns half as much. if she deposited $500 in each account, how much total interest will she have earned in 5 years? a. $34.00 b. $25.50 c. $51.00 d. $510.00

What is 156,420 rounded to the nearest 100,000