多项式乘多项式一个三角形的底边为4M-2``高为2M+1,面积为S.试用含M的代数式表示S.当M=2时,求S.梯形的上底长为(4N+3M)CM,下底长为(2M+5N)CM,它的高为(M+2N)CM,求面积.5x(x^2+2x+1)-(2x+3)(x-5)
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![多项式乘多项式一个三角形的底边为4M-2``高为2M+1,面积为S.试用含M的代数式表示S.当M=2时,求S.梯形的上底长为(4N+3M)CM,下底长为(2M+5N)CM,它的高为(M+2N)CM,求面积.5x(x^2+2x+1)-(2x+3)(x-5)](/uploads/image/z/15232725-45-5.jpg?t=%E5%A4%9A%E9%A1%B9%E5%BC%8F%E4%B9%98%E5%A4%9A%E9%A1%B9%E5%BC%8F%E4%B8%80%E4%B8%AA%E4%B8%89%E8%A7%92%E5%BD%A2%E7%9A%84%E5%BA%95%E8%BE%B9%E4%B8%BA4M-2%60%60%E9%AB%98%E4%B8%BA2M%2B1%2C%E9%9D%A2%E7%A7%AF%E4%B8%BAS.%E8%AF%95%E7%94%A8%E5%90%ABM%E7%9A%84%E4%BB%A3%E6%95%B0%E5%BC%8F%E8%A1%A8%E7%A4%BAS.%E5%BD%93M%3D2%E6%97%B6%2C%E6%B1%82S.%E6%A2%AF%E5%BD%A2%E7%9A%84%E4%B8%8A%E5%BA%95%E9%95%BF%E4%B8%BA%284N%2B3M%29CM%2C%E4%B8%8B%E5%BA%95%E9%95%BF%E4%B8%BA%282M%2B5N%29CM%2C%E5%AE%83%E7%9A%84%E9%AB%98%E4%B8%BA%28M%2B2N%29CM%2C%E6%B1%82%E9%9D%A2%E7%A7%AF.5x%28x%5E2%2B2x%2B1%29-%282x%2B3%29%28x-5%29)
多项式乘多项式一个三角形的底边为4M-2``高为2M+1,面积为S.试用含M的代数式表示S.当M=2时,求S.梯形的上底长为(4N+3M)CM,下底长为(2M+5N)CM,它的高为(M+2N)CM,求面积.5x(x^2+2x+1)-(2x+3)(x-5)
多项式乘多项式
一个三角形的底边为4M-2``高为2M+1,面积为S.试用含M的代数式表示S.当M=2时,求S.
梯形的上底长为(4N+3M)CM,下底长为(2M+5N)CM,它的高为(M+2N)CM,求面积.
5x(x^2+2x+1)-(2x+3)(x-5)
多项式乘多项式一个三角形的底边为4M-2``高为2M+1,面积为S.试用含M的代数式表示S.当M=2时,求S.梯形的上底长为(4N+3M)CM,下底长为(2M+5N)CM,它的高为(M+2N)CM,求面积.5x(x^2+2x+1)-(2x+3)(x-5)
S=(4m-2)(2m+1)/2
=2(2m-1)(2m+1)/2
=4m^2-1
m=2
S=4*2^2-1=15
S=[(4n+3m)+(2m+5n)]*(m+2n)/2
=(9n+5m)(m+2n)/2
=(18n^2+5m^2+19mn)/2
=9n^2+5m^2/2+19mn/2
5x(x^2+2x+1)-(2x+3)(x-5)
=5x^3+10x^2+5x-(2x^2-7x-15)
=5x^3+10x^2+5x-2x^2+7x+15
=5x^3+8x^2+12x+15
1.S=(4M-2)(2M+1)/2=4M^2-1
M=2 => S=15
2.S=[(4N+3M)+(2M+5N)](M+2N)/2
=(5M+9N)(M+2N)/2
=(5M^2+19MN+18N^2)/2
3.5x(x^2+2x+1)-(2x+3)(x-5)
=5x^3+10x^2+5x-2x^2+7x+15
=5x^3+8x^2+12x+15
三角形面积S=(4M-2)(2M+1)/2 当M=2时 S=6*5/2=15
梯形面积:S=(4N+3M+2M+5N)(M+2N)/2=(5M+9N)(M+2N)/2
5X(X^2+2X+1)-(2X+3)(X-5)=5X^3+10X^2+5X-2X^2+15+7X
=5X^3+8X^2+12X+15
1.
S=1/2×底×高=1/2×(4M-2)(2M+1)=(2M-1)(2M+1)=4M^2-1
当M=2时
S=4×2^2-1=15
2.
S=1/2×(上底+下底)×高=1/2(4N+3M+2M+5N)(M+2N)
=(9N+5M)(M+2N)/2
...
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1.
S=1/2×底×高=1/2×(4M-2)(2M+1)=(2M-1)(2M+1)=4M^2-1
当M=2时
S=4×2^2-1=15
2.
S=1/2×(上底+下底)×高=1/2(4N+3M+2M+5N)(M+2N)
=(9N+5M)(M+2N)/2
=(18N^2+19MN+5M^2)/2
3.
5x(x^2+2x+1)-(2x+3)(x-5)
=5x^3+10x^2+5x-(2x^2-7x-15)
=5x^3+8x^2+12x+15
收起
1,S=(4M-2)(2M+1)/2=4M^2-1
当M=2时 S=6*5/2=15
2,梯形面积:S=(4N+3M+2M+5N)(M+2N)/2=(5M+9N)(M+2N)/2
5X(X^2+2X+1)-(2X+3)(X-5)=5X^3+10X^2+5X-2X^2+15+7X
=5X^3+8X^2+12X+15