y=(4+x)*6/2化简得y=3x+12
y=3x+12
因为S梯形=1/2*h*(上底+下底)所以y=1/2*6*(4+x)=3x+12所以得出y=3x+12
x=2y/6-4=y/3-4y=(x+4)*6/2=3x+12
y=3x+12 y=3x+12 y=3x+12