Zadanie 1
a_n=a_1+(n-1)r
a_3=a_1+(3-1)r=4
a_5=a_1+(5-1)r=14
\left \{ {{a_1+(3-1)r=4} \atop {a_1+(5-1)r=14}} \right.
\left \{ {{a_1+2r=4} \atop {a_1+4r=14}} \right.
-2r=-10
r=5
a_1+2*5=4
a_1=-10+4
a_1=-6
a_{10}=-6+(10-1)*5=-6+45
a_{10}=39
S_n=\frac{a_1+a_n}{2}*n
S_{10}=\frac{-6+39}{2}*10=33*5
S_{10}=165
a_1=- 6, r=5, a_{10}=39, S_{10}=165