Question

Calcular o 1º termo da PA: em que a12 = 25 e r= 2
a) 2
b) 4
c) 3
d) 1
e) 5​

Answer 1

$\Large\boxed{\begin{array}{l}\sf a_{12}=a_1+11r\\\sf 25=a_1+11\cdot2\\\sf a_1+22=25\\\sf a_1=25-22\\\sf a_1=3\\\huge\boxed{\boxed{\boxed{\boxed{\sf\maltese~alternativa~c}}}}\end{array}}$

Answer 2

Resposta:

alternativa. ccc

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