Cable decrease at each end of row

Hi. I’m knitting my first cable cardigan. I’ve cast of first 3 stitches at the armhole rows. Now I have to decrease 1 stitch at each end of next and every alternative row.

How do I decrease one stitch when I row ends on a cable 4 st. cable without having a jagged edge?

Decrease on the row after you’ve crossed the cable, and then work those stitches in stockinette for the rest of the way.

Thank you soo much Ingrid - you’ve made my day!