1.已知a2+2a+5=0,则2a2+4a+5=________2.若3b-b+2=0,则-7-9b2+3b=_________3.当x=13时,代数式ax5-6bx+15的值为8,求当x=-13时,ax5-6bx-12=_________4.如果a2+b2=5,那么代数式(3a2-2ab-6a2)-(5a2-2ab-4b2)的值是__________5.已知x2-y2
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![1.已知a2+2a+5=0,则2a2+4a+5=________2.若3b-b+2=0,则-7-9b2+3b=_________3.当x=13时,代数式ax5-6bx+15的值为8,求当x=-13时,ax5-6bx-12=_________4.如果a2+b2=5,那么代数式(3a2-2ab-6a2)-(5a2-2ab-4b2)的值是__________5.已知x2-y2](/uploads/image/z/1710340-52-0.jpg?t=1.%E5%B7%B2%E7%9F%A5a2%2B2a%2B5%3D0%2C%E5%88%992a2%2B4a%2B5%3D________2.%E8%8B%A53b-b%2B2%3D0%2C%E5%88%99-7-9b2%2B3b%3D_________3.%E5%BD%93x%3D13%E6%97%B6%2C%E4%BB%A3%E6%95%B0%E5%BC%8Fax5-6bx%2B15%E7%9A%84%E5%80%BC%E4%B8%BA8%2C%E6%B1%82%E5%BD%93x%3D-13%E6%97%B6%2Cax5-6bx-12%3D_________4.%E5%A6%82%E6%9E%9Ca2%2Bb2%3D5%2C%E9%82%A3%E4%B9%88%E4%BB%A3%E6%95%B0%E5%BC%8F%EF%BC%883a2-2ab-6a2%EF%BC%89-%EF%BC%885a2-2ab-4b2%EF%BC%89%E7%9A%84%E5%80%BC%E6%98%AF__________5.%E5%B7%B2%E7%9F%A5x2-y2)
1.已知a2+2a+5=0,则2a2+4a+5=________2.若3b-b+2=0,则-7-9b2+3b=_________3.当x=13时,代数式ax5-6bx+15的值为8,求当x=-13时,ax5-6bx-12=_________4.如果a2+b2=5,那么代数式(3a2-2ab-6a2)-(5a2-2ab-4b2)的值是__________5.已知x2-y2
1.已知a2+2a+5=0,则2a2+4a+5=________
2.若3b-b+2=0,则-7-9b2+3b=_________
3.当x=13时,代数式ax5-6bx+15的值为8,求当x=-13时,ax5-6bx-12=_________
4.如果a2+b2=5,那么代数式(3a2-2ab-6a2)-(5a2-2ab-4b2)的值是__________
5.已知x2-y2=3,xy=-6,求12xy-3/2x2-5xy+5/3y2-8yx-1/6x2的值.
1.已知a2+2a+5=0,则2a2+4a+5=________2.若3b-b+2=0,则-7-9b2+3b=_________3.当x=13时,代数式ax5-6bx+15的值为8,求当x=-13时,ax5-6bx-12=_________4.如果a2+b2=5,那么代数式(3a2-2ab-6a2)-(5a2-2ab-4b2)的值是__________5.已知x2-y2
第一个问题:首先由第一个式子可得到(a+1)2=-4,又因为第二个式子可以写为2(a+1)2+3所以结果为-1;
第二个:由式子的b=1,可计算出结果
第三个问题:先将ax5-6bx看成一个整体,这样由13变为-13 就只是符号的问题了
第四个:把括号打开就ok啦
第五个问题,将问题中的式子化简就搞定!
小朋友,自己耐心做吧