Postive cable burned, after being replaced car eont start but all lights etc work

Here's a pic

Pic

make sure the terminals are tight , why was it replaced in the first place ?

Looks like quite a hack job on those cables. A loose connection got hot due to the high amperage current going through it causing the insulation to melt. A proper set of replacement battery cables would certainly help.

thank you for answers, got the cable from car quest for 2007 gr prix, should I have gotten both neg and positive cable all in one set instead? mechanic cleaned post and put the goop on it,