Why is 6x-4y+4.8 and-2x+y not linear

Two parallel lines are crossed by a transversal.what is value of x

For f(x)=2x+1 and g(x)= x^2 -7, find (f•g)(x)

Someone answer asap for ! the following statements are true about the coins calvin and sasha have collected. * calvin and sasha has the same amount of money. * calvin has only quarters. * sasha has dimes, nickels, and pennies * calvin has the same number of quarters as sasha has dimes. * sasha has $1.95 in coins that are not dimes. exactly how many quarters does calvin have?