[tex]\large\text{$ PA = ( -4, ~1 , ~6 , ~11 ,~ 16 , ~ 21 , ~ 26 ) ~ $}[/tex]
[tex]\Large\text{$ Progress\tilde{a}o ~Aritm\acute{e}tica $}[/tex]
Encontrar a razão da PA;
[tex]an = ak + ( n - k ).r\\\\11 = 26 + ( 4 - 7 ) . r \\\\11 = 26 - 3.r\\\\11 - 26 = -3. r\\\\-15 / -3 = r\\\\r = 5[/tex]
Encontrar o valor do termo a1 ( Primeiro termo )
[tex]an = a1 + ( n - 1 ) . r\\\\11 = a1 + ( 4 - 1 ) . 5 \\\\11 = a1 + 3 . 5\\\\11 = a1 + 15\\\\11 - 15 = a1\\\\a1 = -4[/tex]
PA ( -4, 1 , 6 , 11 , 16 , .21 , 26 )
===
Para saber mais:
https://brainly.com.br/tarefa/49924917
https://brainly.com.br/tarefa/50652031
https://brainly.com.br/tarefa/50715160
