Carlos's gas tank is 19 full. after he buys 6 gallons of gas, it is 13 full. how many gallons can carlos's tank hold

The graph of f(x) is obtained by reflecting the graph of f(x)=-3|x| over the x-axis. which equation describes f(x)? a) f(x)=3|x| b) f(x)=|x+3| c) f(x)=-3|x| d) f(x) = - |x+3|