Question

Să se determine termenii x,y,z,t ai progresiei aritmetice:x,y,-21,z,-15,t,.....

Answer 1

[tex]\displaystyle\\ \text{Se da progresia aritmetica: } \\ x,~y,~-21,~z,~-15,~t~,..... \\ \\ Se cere:\\ x = ?,~y=?,~z=?,~t=?\\\\ \text{Rezolvare: }\\\\ z = \frac{-21 + (-15)}{2} = \frac{-21 -15}{2} = \frac{-36}{2} = \boxed{-18} \\ \\ \Longrightarrow~~r = -15-z = -15-(-18) = -15 +18 = \boxed{3 ~~(ratia)}\\ t = -15 + r = -15 + 3 = \boxed{-12}\\ y = -21-r = -21 -3 = \boxed{-24}\\ x = y - r = -24 -3 = \boxed{-27} [/tex]