计算:(3a-5b-2c)(-3a-5b+2c)简便算法需过程.

来源:学生作业帮助网 编辑:作业帮 时间:2024/10/05 16:37:46
计算:(3a-5b-2c)(-3a-5b+2c)简便算法需过程.
xAJ@0 Bs@ $K t#n$ ⮔vѫ4t+MBX]yV=YRģOY#G2>6ڌeCymGs[@؄(_jֻuL'Wcy.:3}i+fhe%77CjQ+USH4@"Fǥl@*Bb,Ӕ+EOE<Y-@[y\u~ 5p&@ݚ=L9ۤudr-MSKa J7>

计算:(3a-5b-2c)(-3a-5b+2c)简便算法需过程.
计算:(3a-5b-2c)(-3a-5b+2c)
简便算法需过程.

计算:(3a-5b-2c)(-3a-5b+2c)简便算法需过程.
(3a-5b-2c)(-3a-5b+2c)
=[(3a-2c)-5b][(-(3a-2c)-5b]
=-[(3a-2c)-5b][(3a-2c)+5b]
=-(3a-2c)^2+(5b)^2
=-9a^2-4c^2+12ac+25b^2
吉林 汪清LLX

(3a-5b-2c)(-3a-5b+2c)
=[-5b+(3a-2c)][-5b-(3a-2c)]
=(-5b)^2-(3a-2c)^2
=25b^2-9a^2+12ac-4c^2

1.在第2个括号里提个负号,原式=-(3a-2c-5b)×(3a-2c+5b)=-[(3a-2c)-5b]×[(3a-2b)+5b]=-[(3a-2c)^2-25b^2] =-9a^2+12ac-4c^2+25b^2