Which formula should be used to correctly calculate the monthly mortgage payment? m = p startfraction left-bracket r (1 minus r) superscript n baseline right-bracket over (1 + r) superscript n baseline endfraction m = p startfraction left-bracket r (1 + r) superscript n baseline right-bracket over left-bracket (1 + r) superscript n baseline minus 1 right-bracket endfraction m = p startfraction r over left-bracket (1 + r) superscript n baseline minus 1 right-bracket endfraction m = p startfraction left-bracket r (1 + r) superscript n baseline right-bracket over (n + r) endfraction.