B2=24,b3=12.(b+1), q=b3/b2 = 12.(b+1)/24 = 1/2(b+1)
b1 = b2/q = 24: 1/2(b+1) = 48/(b+1)
b1+b2+b3 = 76
48/(b+1)+ 24 + 12(b+1) = 76
48 /(b+1) +12(b+1) = 76-24
48/(b+1) +12(b+1) = 52 //. (b+1)
48 +12. (b+1)(b+1) = 52(b+1)
48 +12(bˇ2 +2b+1) = 52b +52
12bˇ2 +24b +12 =52b+4
12bˇ2-28b+8=0, 3bˇ2 -7b+2=0
b=2, b=1/3
a)b=2 , b3=36, 3/2,b1=16, 16+24+36=76
b)b=1/3: b3=16,b1 = 36, 36+24+16=76