40 POINTS PLEASE HELP!

1. Consider the system of equations
5x - 2y = 16,
15x - 7y = 51.

Multiply the first equation by some constant, so that in the resulting equation, the coefficient of x matches the coefficient of x in the second equation.

Enter the entire equation that results from multiplying the first equation by the constant.


2.The ordered pair (x,y)=(8, 6) is the solution of the following system of linear equations

x = 1/10y + a
y= 1/10x + b
Find the value of a + b.

3. Alice and Bob each have a certain amount of money. If Alice receives n dollars from Bob, then she will have 3 times as much money as Bob. If, on the other hand, she gives n dollars to Bob, then she will have 2 times as much money as Bob. If neither gives the other any money, what is the ratio of the amount of money Alice has to the amount Bob has?

A pen and a pencil together cost 1.10. The pen costs a dollar more than the pencil. How much does the pen cost?