数学公因式法告诉我第一题的8个小题,关键、重点是要你们写出过程,我特别想看过程!
8个回答
1.x²-81
原式=(x+9)(x-9)
2.1/4×a²-b²
原式=1/4(a+b)(a-b)
3.9(x-y)²-25
原式=[3(x-y)+5][3(x-y)-5]
4.(x²-y)²-(2y-2)²
原式=[(x²-y)+(2y-2)][(x²-y)-(2y-2)]
=(x²-y+2y-2)(x²-y-2y+2)
=(x²+y-2)(x²-3y+2)
5.x^4-81
原式=(x²+9)(x²-9)
=(x²+9)(x+3)(x-3)
6.3x^6-3x²
原式=3x²(x^4-1)
=3x²(x²+1)(x²-1)
=3x²(x²+1)(x+1)(x-1)
7.(a²-2b)²-(1-2b)²
原式=[(a²-2b)+(1-2b)][(a²-2b)-(1-2b)]
=(a²-2b+1-2b)(a²-2b-1+2b)
=(a²-4b+1)(a²-1)
=(a²-4b+1)(a+1)(a-1)
8.9x^4-36y²
原式=9(x^4-4y²)
=9(x²+2y)(x²-2y)
