- 解答题目.因式分解(要有步骤)1。2ax+3bx+4ay+6by?
- 解答题目.因式分解(要有步骤)
1。2ax+3bx+4ay+6by
2.(x-2y)²+4xy-8y+4
3。已知实数a.b满足(a+b)²=1,(a-b)²=25,求证a²+b²+ab的值。
3。用公式计算
998*1002 2008-4016-3
- 1.
2ax+3bx+4ay+6by
=(2ax+4ay)+(3bx+6by)
=2a(x+2y)+3b(x+2y)
=(x+2y)(2a+3b)
2.
(x-2y)²+4xy-8y+4
=(x²-4xy+4y²)+4xy-8y+4
=x²+4y²-8y+4
=x²+4(y-1)².......在实数范围内无法分解,是不是题目抄错了?
3.已知实数a.b满足(a+b)²=1,求证a²+b²+ab的值。
(a+b)²=a²+2ab+b²=1..........①
(a-b)²=a²-2ab+b²=25.........②
(①×3+②)/ 4 得
[(3a²+6ab+3b²)+(a²-2ab+b²)]/4
=(4a²+4b²+4ab)/4
=a²+b²+ab
=(1×3+25)/4
=7
3.
998*1002
=(1000-2)×(1000+2)
=1000²-2²
=00-4
=999996
2008-4016-3
=2008-2×2008-3
=(1-2)×2008-3
=-2008-3
=-2011