2x+ 4y = 16 through ( 12,15)

I just don’t get this one.

Lee has $1.75 in dimes and nickels. the number of nickels is 11 more than the number of dimes. how many of each coin does he have?

Marla bought a book for $12.95, a binder for $3.49, and a backpack for $44.99. the sales tax rate is 6%. find the amount of tax and the total she paid for these items

Which graph represents the parent function of y=(x+2)(x-2)