Question 959046

{{{90/(1 - r)+100^0/(1 - r)=90/(1 - r)+1/(1 - r)=(90+1)/(1 - r)=91/(1 - r)}}}


{{{(4s^3 -1)/s^2+s^0/s^2=(4s^3 -1)/s^2+1/s^2=(4s^3 -cross(1)+cross(1))/s^2=4s^3 /s^2=4s^cross(3)^1 /cross(s^2)1=4s}}}