题目内容
已知==且3x+2y-4z=-8,求x,y,z的值.
解:令===k(k≠0),则解得x=2k,y=k.z=3k,代入方程3x+2y-4z=-8中,得6k+2k-12k=-8,所以k=2,所以x=4,y=2,z=6.
(1)分解因式:4x6y2+4x5y-24x6=_____________.
(2)分解因式:x2-16y2-8y-1=_____________.
(3)分解因式:x2-2xy+y2+2x-2y-8=_____________.
(4)分解因式:a2(b2-c2)-c2(b+c)(b-c)=_____________.
(5)分解因式:(x2+x-6)(x2+x-8)-24=_____________.
(6)若x2+mx+n是一个完全平方式,则m、n的关系是_____________.
(7)若18x2+mx+5=(9x-5)(2x-1),则m=_____________.
(8)若a+b=3,ab=-2,则a3+a2b+ab2+b3=_____________.
(9)a、b、c是△ABC的三边,且a2+b2+c2=ab+ac+bc,则△ABC是_____________三角形.
(10)已知a+=3,则a2+的值是_____________.
(11)若x2+3x-4=(x+a)(x+b),则的值是_____________.
(12)若4a2+9b2-4a+12b+5=0,则a=_____________,b=_____________.
已知方程组,且3x-2y=a,求a的值.
已知A=2x2-3xy+y2-x+2y,B=4x2-6xy+2y2+3x-y,若|x-2a|+(y+3)2=0且B-2A=a,求a的值.
已知2x-3y+z=0,3x-2y=6z,且xyz≠0,求的值.