With both questions .

explain the pattern of forming the future tense for the verbs poner, salir, and venir.

explain why the expression dudo que takes the subjunctive while no dudo que does not.

eliminate the ending IR

add to the root

yodre(acento en A)

tu            dras (acento en A)

el/ella       dra(acento en A)

n              dremos

vdreis(acento en E)

ellos/ellas    dran (Aacento en A)

Both take  subuntivo if the first part of the sentence is in present.

Dudo que vengas/No dudo que vengas

If the first part is in past:

Dudaba/Dude(acento en E) que vinieras/No  dudaba/No dude que vinieras

The pattern of forming the future of these verb which are irregular is as follow

Poner became in pondr as a root, salir  in saldr and venir in vendr

The ending of these verb will depend on the person that is conjugated

for example the verb poner will stay like this

Yo pondré

Tu pondrás

El- Ella  pondrá

Nosotros pondremos

Vosotros pondreís

Ellos -Ellas pondrán

The same rule for these ending applies to the verbs salir and venir.