Step-by-step explanation:
Volume= [(20+20) x (20+20) x 100] - (20 x 20 x 100)
=120000cm^3
surface area= 2 x 40 x 100 + 2 x (40 x 40 - 20 x 20) + 4 x 20 x 100
=18400cm^2
3x - y = 9
4x + y = 5
---------------add
7x = 14
x = 14/7
x = 2
3x - y = 9
3(2) - y = 9
6 - y = 9
-y = 9 - 6
-y = 3
y = -3
C. (2,-3) is a solution to the system of linear equations
