If f(5)=a what is the value of a

Is this a polynomial function? i need to know asap

John used linear combination to solve the system of equations shown. he did so by multiplying the first equation by -3 and the second equation by another number to eliminate the x-terms. what number did jonas multiply the second equation by? 4x-6y=23x+5y=11

Order the measurements from the least to the greatest. 2,720 ml , 24.91 l , 0.0268 kl