Given, y2=4x...(1)
y=2x−4⇒2x=y+4...(2)
Solving equations (1)&(2), we get
⇒y2=2y+8
⇒y2−2y−8=0
⇒(y−4)(y+2)=0
⇒y=4,−2
From equation (2),
If y=4 then x=4 and if y=−2 then x=1.

A=[∫04(4x)dx−21×2×4]+[∫014xdx]+21×1×2
=2[23x3/2]04−4+2[23x3/2]01+1
=34[8]−4+34[1]+1
=336−3
=9