a= 6-2b-3c
then put that equation inside the first one and then the second one
you get -6*(6-2b-3c)+2b-3c=23
and 5*(6-2b-3c)+4b-3c=-12
14b-15c=59
14b-18c=18/*(-1)
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3b=41
Volume=4/3 pi r^3. so 4/3 pi r^3 = 500/3 pi. Therefore, divide by pi, and multiply by 3, you get 4r^3=500. Divide by 4 to get r^3=125, and cube root to result in 25. r=25.
I think it may be 5+3 and carry the one up top to get the sum of 56.
The answer is A, yes his answer is reasonable because 6 times 0.74 is 44.4