Question

b4-b2=18 b5-b3=36 Найти b1

Answer 1

$left { {{ b_{4} - b_{2} =18} atop { b_{5} - b_{3} =36}} right. left { {{ b_{1}q^3- b_{1}q=18 } atop {b_{1}q^4- b_{1}q^2=36}} right. left { {{b_{1}q(q^2-1)=18} atop {b_{1}q^2( q^2-1)=36}} right. left { {{b_{1}= frac{18}{q(q^2-1)} } atop {b_{1}q^2( q^2-1)=36}} right. left { {{b_{1}= frac{18}{q(q^2-1)} atop {q= frac{36}{18} }}$

$left { {{b_{1}= frac{18}{q(q^2-1)} atop {q= frac{36}{18} }} left { {{b_{1}= frac{18}{2(2^2-1)} atop {q=2}} right. left { {{b_{1}= frac{18}{6} atop {q=2}} right. b_{1}=3$

Answer 2

Спс