Solve the system of equations by substitution
y = 2x - 4
7x - 2y = 5

12. the amount of money in a bank account decreased by 21.5% over the last year. if the amount of money at the beginning of the year is represented by ‘n', write 3 equivalent expressions to represent the amount of money in the bank account after the decrease?

Simplify the expression. -2/5(10+15m-20n)

Acollection of nickels and quarters is worth $2.85. there are 3 more nickels than quarters.how many nickels and quarters are there?