Where did you get this monster? It has taken me three days to figure it out! I tried the quadratic formula( no ='s anything was the hint ) to no avail, but I decided this approach is best. Attend. By the way, that is 52X!
Factor area expression
4X^2 + 52X + 168
4(X^2 + 13X + 42)
4(X + 6)(X + 7)
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Factor height expression.
X/4X + 28
X/4(X + 7)
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Multiply area by height to get volume.
Volume = {4(X + 6)(X+7)}{X/4(X + 7)}
See the 4 and X + 7 repeats? They disappear.
V = {(X + 6/1)}{X/1}
V = X(X + 6)/1
V = X(X + 6)
V = X^2 + 6X
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