已知m²-mn=20,n²-mn=-12,求代数式m²-n²与m²-2mn+n²的值3²-1²=8=8x1,5²-3²=16=8x2,7²-5²=32=8x3,.若a²-b²=64=8x8,a=( ),b=( ).第n个式子是
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![已知m²-mn=20,n²-mn=-12,求代数式m²-n²与m²-2mn+n²的值3²-1²=8=8x1,5²-3²=16=8x2,7²-5²=32=8x3,.若a²-b²=64=8x8,a=( ),b=( ).第n个式子是](/uploads/image/z/336582-54-2.jpg?t=%E5%B7%B2%E7%9F%A5m%26%23178%3B-mn%3D20%2Cn%26%23178%3B-mn%3D-12%2C%E6%B1%82%E4%BB%A3%E6%95%B0%E5%BC%8Fm%26%23178%3B-n%26%23178%3B%E4%B8%8Em%26%23178%3B-2mn%2Bn%26%23178%3B%E7%9A%84%E5%80%BC3%26%23178%3B-1%26%23178%3B%3D8%3D8x1%2C5%26%23178%3B-3%26%23178%3B%3D16%3D8x2%2C7%26%23178%3B-5%26%23178%3B%3D32%3D8x3%2C.%E8%8B%A5a%26%23178%3B-b%26%23178%3B%3D64%3D8x8%2Ca%3D%28+%29%2Cb%3D%28+%29.%E7%AC%ACn%E4%B8%AA%E5%BC%8F%E5%AD%90%E6%98%AF)
已知m²-mn=20,n²-mn=-12,求代数式m²-n²与m²-2mn+n²的值3²-1²=8=8x1,5²-3²=16=8x2,7²-5²=32=8x3,.若a²-b²=64=8x8,a=( ),b=( ).第n个式子是
已知m²-mn=20,n²-mn=-12,求代数式m²-n²与m²-2mn+n²的值
3²-1²=8=8x1,5²-3²=16=8x2,7²-5²=32=8x3,.若a²-b²=64=8x8,a=( ),b=( ).第n个式子是
已知m²-mn=20,n²-mn=-12,求代数式m²-n²与m²-2mn+n²的值3²-1²=8=8x1,5²-3²=16=8x2,7²-5²=32=8x3,.若a²-b²=64=8x8,a=( ),b=( ).第n个式子是
1 两式相减 得m²-n²=32
两式相加 得m²-2mn+n²=18
2 由题可知 n个式子为(2n+1)²-(2n-1)²=8n
因此a=17 b=15
m²-mn=20,n²-mn=-12
m²-n²=(m²-mn)-(n²-mn)=20-(-12)=32
m²-2mn+n²=(m²-mn)+(n²-mn)=20+(-12)=8
若a²-b²=64=8x8,a=( 17),b=( 15).
第n个式子是(2n+1)²-(2n-1)²=8n
m²-n²=(m²-mn)-(n²-mn)=20-(-12)=32
m²-2mn+n²=(m²-mn)+(n²-mn)=20+(-12)=8
3²-1²=(2×1+1)²-(2×1-1)²=8×1
5²-3²=(2×2+1)²...
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m²-n²=(m²-mn)-(n²-mn)=20-(-12)=32
m²-2mn+n²=(m²-mn)+(n²-mn)=20+(-12)=8
3²-1²=(2×1+1)²-(2×1-1)²=8×1
5²-3²=(2×2+1)²-(2×2-1)²=8×2
7²-5²=(2×3+1)²-(2×3-1)²=8×3
…………
a²-b²=8×8
a=2×8+1=17 b=2×8-1=15
第n个式子:(2n+1)²-(2n-1)²=8n
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