A geometric progression has a second term of 12 and a sum to infinity of 54. Find the possible values of the first term of the progression
ar=12, a1−r=54.ar=12, \;\frac{a}{1-r}=54.ar=12,1−ra=54.
r=12a, a2a−12=54.r=\frac{12}{a},\;\frac{a^2}{a-12}=54.r=a12,a−12a2=54.
a2−54a+648=0.a^2-54a+648=0.a2−54a+648=0.
a=18, a=36.a=18,\;a=36.a=18,a=36.
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