dari barisan aritmatika u2=7dan us=-2 maka s10=

[tex]U_2=7 \\ U_5=-2 \\ \\ b = \frac{7 - ( - 2)}{2 - 5} = \frac{9}{ - 3} = - 3 \\ a = 7 - ( - 3) = 10 \\ \\ U_{10} = 10 + 9( - 3) = - 17\\ \\ S_{10} = \frac{10}{2} (10 + ( - 17)) \\ = 5( - 7) \\ = - 35[/tex]