"The house's windows are closed."
Translation:घर की खिड़कियाँ बंद हैं।
Some adjectives change with the gender/number of the subject and others don't.
The rule of thumb is that adjectives ending in ा for a direct-case masculine singular subject change form (with the ending becoming ी for feminine subjects and े for plural/oblique-case masculine subjects) and adjectives ending with anything else don't change form. However, there are a few exceptions to the rule such as तनहा (solitary) and ज़्यादा (more) which don't change form.