三道七年级因式分解数学题.高手进
\u4e09\u9053\u4e03\u5e74\u7ea7\u6570\u5b66\u9898\uff0c\u6709\u5173\u56e0\u5f0f\u5206\u89e3\uff0c\u6c42\u9ad8\u624b\u4e3a\u6211\u89e3\u7b54\uff01\u4e00\u3001\u539f\u5f0f\uff1d\uff08x²\uff0b5x\uff0b4\uff09\uff08x²\uff0b5x\uff0b6\uff09\uff0b1
\uff1d\uff08x²\uff0b5x\uff0b4\uff09²\uff0b2\uff08x²\uff0b5x\uff0b4\uff09\uff0b1
\uff1d\uff08x²\uff0b5x\uff0b5\uff09²
\u4e8c\u3001 \u8bbex²+y²=A,\u90a3\u4e48\uff08x²+y²\uff09\uff08x²+3+y²\uff09-54=0\uff0c\u53ef\u53d8\u4e3aA\uff08A+3\uff09-54=0
A²+3A-54=0 (A-6)(A+9)=0 A1=6 A2=-9\uff08\u820d\uff09
\u4e5f\u5c31\u662fx²+y²=6
x²+xy-2y²=7
\uff08x+2y\uff09\uff08x-y\uff09=7
7=1\u00d77\u4e14x\uff0cy\u90fd\u662f\u6b63\u6574\u6570
\u6240\u4ee5x+2y\uff1ex-y
x+2y=7
x-y=1
\u89e3\u5f973y=6
y=2
x=3
=a[(x^2-2x)^2+2(x^2-2x)+1]
=a(x^2-2x+1)^2
=a(x-1)^4
2. （t平方+2t）平方+2（t平方+2t）+1
令t^2+2t=x
原式=x^2+2x+1=(x+1)^2
(x+1)^2=(t^2+2t+1)^2=(t+1)^4
当t=-3时 (t+1)^4 =(-3+ 1)^4=(-2)^4=16
3. x平方+2（k-3）x+25
=(x+-5)^2=x^2+-2*1*5x+5^2
（k-3)=5 k=8
k-3=-5 k = -2
1.a(x²-2x)²-2ax(2-x)+a
=a[x²(x-2)²+2x(x-2)+1]
=a[x(x-2)+1]²
=a(x²-2x+1)²
=a(x-1)的四次方 [即a乘以4个(x-1)]
2.(t²+2t)² + 2(t²+2t) +1
=(t²+2t +1)²=(t+1)的四次方
当t=-3时,原式=(-3+1)的四次方=16
3.设这个完全平方式是(x+5)²,则:
2（k-3）=10 k=8
祝你进步!
（1）a(x平方-2x)平方-2ax(2-x)+a
=a[(x平方-2x)平方+2(x2-2x)+1]
=a(x平方-2x-1)平方
=a(x-1)4次方
（2）(t2+2t)平方+2(t2+2t)+1
=(t+1)4次方 当t=3时，原式=256
（3）∵x平方+2(k-3)+25是完全平方式
∴k-3=正负根号25
k-3=正负5
k=8或-2
1.=a(x-1)^4
2.=(t+1)^4,当t=-3时的值为16
3.K为8
1.a(x^2-2x)^2-2ax(2-x)+a
=a[x(x-2)]^2+2ax(x-2)+a
=ax^2(x-2)^2+2ax(x-2)+a
=a[x^2(x-2)^2+2x(x-2)+1]
=a[x(x-2)+1]^2
=a(x^2-2x+1)^2
=a(x-1)^4
2.(t^2+2t)^2+2(t^2+2t)+1
=(t^2+2t+1)^2
=(t+1)^4
当t=-3时，原式=(-3+1)^4=16
3.(x+5)^2=x^2+25+10x
则2(k-3)=10
k-3=5
k=8
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