Question 262600
(1/2)r(r+1)-36=0
r(r+1)/2=36
r^2+r=72
r^2+r-72=0
r^2 +9r-8r-72=0
r(r+9) -8(r+9)=0
(r+9)(r-8)=0

R= -9  or 8

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