4m^2+8mn+3n^2因式分解题
解几道向量的题
1设向量m的绝对值为1,向量n的绝对值为2,2m+n与m-3n垂直,a=4m-n,b=7m+2n,则向量a和b的夹角为___解:2m+n与m-3n垂直,∴0=(2m+n)(m-3n)=2m^2-5mn-3n^2=5-5mn,∴mn=1.a^2=16m^2-8mn+n^2=64-8+1=57,a=√57.b^2=49m^2+28mn+4n^2=228,b=2√57.ab=(4m-...
10个奇数的平方之和 除以8,为什么余2
任意一个奇数都可以表示成如下形式:4m+n,m为整数,n=1,3。 (4m+n)^2=16m^2+8mn+n^2=8(2m^2+mn)+n^2,8(2m^2+mn)显然能被8整除;n^2={1,n=1时;9,n=3时},所以8除n^2余数为1,所以8除任意一个奇数的平方余数为1;又由于8除10余2,所以8除任意10个奇数的平方和...
若已知mn=8,且m,n都是整数,试求2m^2+2n^2的最小值
m,n都是正整数,则m^2+n^2>=2mn=2*8=16,等号仅当m=n时成立。所以2m^2+2n^2=2(m^2+n^2)>=2*16=32,最小值是32
已知有理数m,n满足(m+n)²=9,(m-n)²=1。求(1)mn (2)m²+n²...
(1) (m+n)^2=9...(1)(m-n)^2=1...(2)(1)-(2): (m+n+m-n)(m+n-(m-n))=8 2m*2n=8 mn=2 (2) (m+n)^2=9 m^2+n^2+2mn=9 m^2+n^2-mn=9-3mn=9-3*2=3
分解因式:(1) 9x+1\/4+81x^2 (2) -m^2n^2-16+8mn (3) (y+2
回答:(1) 9x+1\/4+81x^2=(9x+1\/2)^2 2) -m^2n^2-16+8mn=-(mn-4)^2
帮忙解答几道七年级计算题,请写下完整步骤,谢谢!
1)25m^2+40mn+16n^4 2)m^2+2mn+n^2-2m^2+2+4m^2-8mn+4n^2=3m^2-6mn+5n^2+2 3)(2a+4b)(m-n)
已知m-2n=5,mn=3,m>0求:(1)m^2+4n^2 (2)m+2n (3)n^2-m^2
mn=3,m>0 n>0 m-2n=5 m=2n+5 mn=3 n(2n+5)=3 2n^2+5n-3=0 (2n-1)(n+3)=0 n=1\/2或n=-3(舍去)m=2n+5 =2*1\/2+5 =5 m^2+4n^2 =5^2+4*(1\/2)^2 =25+1 =26 m+2n =5+2*1\/2 =5+1 =6 n^2-m^2 =(1\/2)^2-5^2 =1\/4-25 =-99\/4 ...
若m的平方加n的平方等于八,mn等于二分之一,则m加n的值等于 A.3 B...
(M+n)^2=m^2+2mn+n2 =8+2*1\/2 =9 所以选C
...元二次方程x的平方+mx+n=0的一个根,求二次根式√(8m的平方-8mn...
解 :化简根式 = 因为-2是二次方程式的一个解 所以将-2代入方程式可得2m-n=-4 将上式带入化简后的根式 可得根式4倍的根号2
...3(2x的平方-x-2) 3(2a-3b)-(3a-2b)+5(a+b) mn+3(m的平方n)-4(mn...
2(x-3x的平方+1)-3(2x的平方-x-2)=2x-6x^2+2-6x^2+3x+6 =5x-12x^2+8 3(2a-3b)-(3a-2b)+5(a+b)=6a-9b-3a+2b+5a+5b =8a-2b mn+3(m的平方n)-4(mn-2m的平方n)=mn+3m^2n-4mn+8m^2n =11m^2n-3mn
爨萍悦康: 原式=4m^2+8mn-4n^2-4n^2+3n^2=(2m+2n)^2-n^2=(2m+2n+n)(2m+2n-n)=(2m+3n)(2m+n)
达坂城区15978846981: 4m^2+8m+3因式分解十字组 - ?
爨萍悦康: 4m” + 8m + 3 = 4m” + 2m + 6m + 3 = 2m( 2m + 1 ) + 3( 2m + 1 ) = ( 2m + 1 )( 2m + 3 ) 或者 = 4m” + 6m + 2m + 3 = 2m( 2m + 3 ) + ( 2m + 3 ) = ( 2m + 1 )( 2m + 3 ) 或者配方 = 4m” + 8m + 4 - 1 = 4( m” + 2m + 1 ) - 1 = 2”( m + 1 )” - 1 = ( 2m + 2 )” - 1” = ( 2m + 2 - 1 )( 2m + 2 + 1 ) = ( 2m + 1 )( 2m + 3 )
达坂城区15978846981: m^2+4mn+3n^2的因式分解? - ?
爨萍悦康: m^2+4mn+3n^2=(m+3n)(m+n)
达坂城区15978846981: 分解因式:4m^2+p(m+n)^2+12m(m+n)?
爨萍悦康: 4m2+p(m+n)2+12m(m+n) =4m2+12m(m+n) +3(m+n)2 -3(m+n)2+p(m+n)2 =(2m+√3(m+n))2 –(3-p) (m+n)2 =(2m+√3(m+n)+ √(3-p) (m+n))(2m+√3(m+n)- √(3-p) (m+n)) ={[2+√3+ √(3-p)]m+[√3+ √(3-p)]n}{[2+√3- √(3-p)]m+[√3- √(3-p)]n }如果题目中的P是3的话,就很简单了,也更像数学题.
达坂城区15978846981: 分解因式4m^3+4m^2n - 9mn^2 - 9n^3 ax^2=ax - bx - b - 3x^2 - 2x^2y^2+6xy (2x^3 - 4)+(x^2 - 8x) 4x^2 - y^2 - 4x - 2y?
爨萍悦康: (1)4m^3+4m^2n-9mn^2-9n^3 =4m^2(m+n)-9n^2(m+n)=(4m^2-9n^2)(m+n) =(2m-3n)(2m+3m)(m+n) (2) ax^2+ax-bx-b= ax^2-bx+ax-b=x(ax-b)+(ax-b)=(x+1)(ax-b) (3)x^3y-3x^2-2x^2y^2+6xy =x^2(xy-3)-2xy(xy-3)=(x^2-2xy)(xy-3) (4)(2x^3-4)+(x^2-8x)=2x^3...
达坂城区15978846981: 分解因式:4m^2 - 4m+2n - n^2 - ?
爨萍悦康: 4m^2-n^2-(4m-2n)=(2m+n)(2m-n)-2(2m-n)=(2m-n)(2m+n-2)楼主拜托采纳马上升级了,谢谢.
达坂城区15978846981: 若2m+n=3,则4m^2+8mn+n^2 - 6的值为 - ?
爨萍悦康:[答案] (2m+n)^2=4m^2+4mn+n^2=9 4m^2+8mn+n^2-6=(4m^2+4mn+n^2)+4mn-6=9+4mn-6=4mn+3
达坂城区15978846981: 因式分解4m的5次方+8m的三次方n的四次方 - 12mn的四次方 - ?
爨萍悦康: 4m的5次方+8m³n的4次方-12mn的4次方=4m(m的4次方+2m²n的4次方-3m的4次方) 直接提出公因式4m就行了!
达坂城区15978846981: m - 4mn+3n 用配方法进行因式分解 - ?
爨萍悦康:[答案] 原式=m^2-4mn+n^2-n^2+3n^2 =m^2-4mn+4n^2-n^2 =(m-2n)^2-n^2 =(m-2n-n)(m-n+n) =m(m-3n) 满意请点右下角的采纳谢,不满意请追问,您的支持是我奋斗的动力
达坂城区15978846981: 还有一道题需请教:4m²+8mn+3n² - ?
爨萍悦康: (2m+n)(2m+3n)