j - m/4 = 4k for m

j - m/4 = 4k for m

Multiply each side by 4:
4j - 4m/4 = 4(4k)

Simplify:
4j - m = 16k

Add m to each side:
4j - m + m = 16k + m

The m's cancel on the left side, so we have:
4j = 16k + m

Subtract 16k from each side:
4j - 16k = 16k - 16k + m

The 16k cancels on the right side, so we're left with:
m = 4j - 16k or 4(j - 4k)