kak bantu jawab ya,besok dikumpulkan. dengan cara ya kaka . makasih

3. a=1 r=-3/4
S~=a/1-r
S~=1/1-(-3/4)
=1/4/4-(-3/4)
=1/7/4
=1×4/7
=4/7

4. a=27 r=-9/27 r=-1/3
S~=27/1-(-1/3)
=27/3/3-(-1/3)
=27/4/3
=27×3/4
=81/4