北師大版八年級(jí)數(shù)學(xué)下冊(cè)-完全平方公式(提高)鞏固練習(xí)-含答案解析

2(m3)x16m）若x2）222④1個(gè)2個(gè)3個(gè)4個(gè)）⑤．4mma21b1181bb22b2216168a222）0若ab3B．1C．2D．32a4b622）6xcc若xx2（）c0c9c0c9+2=．2n4mnm2222x2x1y22y4x2y50xy若x當(dāng)xx=，226x102．22三.解答題bab5ab2ab2a2，4422=））．2cabc202221bc20(a2abb)(c2bcb)0.a2222222即abbc022∵ab0,bc0ab,bc即abc.22c2abc022m3m或1.②③⑤111122ab4ma2abbab4m2b【解析】a2222242=2=2=22ab62361222.6xcx3c9c90c9x2.222+2=+2=2．nmnm22；22n4mnmn2mn2mnmn.m22222222221yx1yx2x1yx1yx1yx1yx2.222y4x2y5x2y10，x2,y1xy1.x22以226x10x31x3x22．22222，∴==．．babab2ababa44224422222abab222222abab5將ab22222ab252222ab922∵a∴ab2b222=）2）2）+223．2ab2c220222∴a22abbbbcca2acc022222abbcac0222ab0c0∴bac0∴abc42n4mnmn2mn2mnmn.m22222222221yx1yx2x1yx1yx1yx1yx2.222y4x2y5x2y10，x2,y1xy1.x22以226x10x31x3x22．22222，∴==．．babab2ababa44224422222abab222222abab5將ab22222ab252222ab922∵a∴ab2b222=）2）2）+223．2ab2c220222∴a22abbbbcca2acc022222abbcac0222ab0c0∴bac0∴abc42n4mnmn2mn2mnmn.m22222222221yx1yx2x1yx1yx1yx1yx2.222y4x2y5x2y10，x2,y1xy1.x22以226x10x31x3x22．22222，∴==．．babab2ababa44224422222abab222222abab5將ab22222ab252222ab922∵a∴ab2b222=）2）2）+223．2ab2c220222∴a22abbbbcca2acc022222abbcac0222ab0c0∴bac0∴abc42n4mnmn2mn2mnmn.m22222222221yx1yx2x1yx1yx1yx1yx2.222y4x2y5x2y10，x2,y1xy1.x22以226x10x31x3x22．22222，∴==．．babab2ababa44224422222abab222222abab5將ab22222ab252222ab922∵a∴ab2b222=）