how do you combine like terms to this problem -2(j^2-k)-6(j^2+3k)

how do you combine like terms to this problem

$$-2(j^2-k)-6(j^2+3k) \\
=-2j^2+2k-6j^2-18k \\
=-2j^2-6j^2+2k-18k \\
= j^2(-2-6)+k(2-18) \\
=j_2(-8)+k(-16)\\
=j_2(-8)+k(-2*8)\\
=j_2(-8)+k(2)(-8)\\
=(-8)(j^2+2k) \\
=-8(j^2+2k)$$