factorise this fully x2+3x-21
x=-7, x=3
dfgdfgd
dfgdd
asdsaasf
sdas
dfgfdgsgdsr
sdesfdfs
asdasadawfdq
fgdgd
sgert3rte
nfnfghgf
drgegdfg
htmyjmyh
hjgtthg
dfgethrh
fghnfggnf
fghjfgjfgj
k,jh