①9x²-16y²②100-(3x+2y)²③-1+16x²④a²b³-4a²b⑤16x^4-y^4⑥(2x+1)²-x²⑦6.4²-3.6²⑧1.4²×9-2.3²×36⑨x^4-x²
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/02 06:13:18
![①9x²-16y²②100-(3x+2y)²③-1+16x²④a²b³-4a²b⑤16x^4-y^4⑥(2x+1)²-x²⑦6.4²-3.6²⑧1.4²×9-2.3²×36⑨x^4-x²](/uploads/image/z/642689-17-9.jpg?t=%E2%91%A09x%26%23178%3B-16y%26%23178%3B%E2%91%A1100-%EF%BC%883x%2B2y%29%26%23178%3B%E2%91%A2-1%2B16x%26%23178%3B%E2%91%A3a%26%23178%3Bb%26%23179%3B-4a%26%23178%3Bb%E2%91%A416x%5E4-y%5E4%E2%91%A5%EF%BC%882x%2B1%EF%BC%89%26%23178%3B-x%26%23178%3B%E2%91%A66.4%26%23178%3B-3.6%26%23178%3B%E2%91%A71.4%26%23178%3B%C3%979-2.3%26%23178%3B%C3%9736%E2%91%A8x%5E4-x%26%23178%3B)
①9x²-16y²②100-(3x+2y)²③-1+16x²④a²b³-4a²b⑤16x^4-y^4⑥(2x+1)²-x²⑦6.4²-3.6²⑧1.4²×9-2.3²×36⑨x^4-x²
①9x²-16y²②100-(3x+2y)²③-1+16x²④a²b³-4a²b⑤16x^4-y^4⑥(2x+1)²-x²⑦6.4²-3.6²⑧1.4²×9-2.3²×36⑨x^4-x²
①9x²-16y²②100-(3x+2y)²③-1+16x²④a²b³-4a²b⑤16x^4-y^4⑥(2x+1)²-x²⑦6.4²-3.6²⑧1.4²×9-2.3²×36⑨x^4-x²
(1)
9x²-16y²
=(3x)²-(4y)²
=(3x+4y)(3x-4y)
(2)
100-(3x+2y)²
=10²-(3x+2y)²
=[10+(3x+2y)][10-(3x+2y)]
=(3x+2y+10)(10-3x-2y)
(3)
-1+16x²
=(4x)²-1
=(4x+1)(4x-1)
(4)
a²b³-4a²b
=a²b(b²-4)
=a²b(b+2)(b-2)
⑤
16x^4-y^4
=(4x²+y²)(4x²-y²)
=(4x²+y²)(2x+y)(2x-y)
⑥
(2x+1)²-x²
=[(2x+1)+x][(2x+1)-x]
=(3x+1)(x+1)
⑦
6.4²-3.6²
=(6.4+3.6)(6.4-3.6)
=10x2.8
=28
⑧
1.4²×9-2.3²×36
=(1.4x3)²-(2.3x6)²
=4.2²-13.8²
=(4.2+13.8)(4.2-13.8)
=18x(-9.6)
= -172.8
⑨
x^4-x²
=(x²+1)(x²-1)
=(x²+1)(x+1)(x-1)
是代入吗?第一题怎么能算出实数?
①9x²-16y²
=(3x)²-(4y)²
=(3x+4y)(3x-4y)
②100-(3X+2y)^2
=10^2-(3X+2y)^2 平方差公式
=(10+3x+2y)(10-3x-2y)
③-1+16x²
=1²+(4x)²