1二次根式要题随堂演练1.(2018·达州中考)二次根式2x+4中的x的取值范围是()A.x<-2B.x≤-2C.x>-2D.x≥-22.(2018·杭州中考)化简(-2)2的结果是()A.-2B.±2C.2D.43.(2018·无锡中考)下列等式正确的是()A.(3)2=3B.(-3)2=-3C.33=3D.(-3)2=-34.若x+y-1+(y+2)2=0,则x-y的值为()A.-5B.-1C.1D.55.(2017·广饶模拟)计算:3(3+27)=________.6.(2018·广州中考)如图,数轴上点A表示的数为a,化简:a+a2-4a+4=________.7.(2017·青岛中考)计算:(24+16)×6=________.8.计算:13+1-sin60°+32×18.参考答案1.D2.C3.A4.D5.126.27.138.解:原式=3-12-32+2=32-12-32+2=32.