MATHS questions (10分!!)

Angel15

2007-11-27 6:55 am

Factorize the following questions by using identity.
1. -2+162y*
2. 2-18(a+1)*
3. 9p*-q*-12p-4q
4. m(x+y)*-4m(x-y)*
5. x*y(4次方)-16x*
6. 18a*+15b-50b*-9a
ps:' * ' = 2次方
thx for your help~

回答 (1)

Doremidokkan22

2007-11-27 8:01 am

✔ 最佳答案

1. -2+162y*
=-2(1-81y^2)
=-2(1-9y)(1+9y)

2. 2-18(a+1)*
=2-18(a^2+2a+1)
=2-18a^2-36-18
=-18a^2-36a-16
=-2(9a^2+18a+8)
=-2(3a+4)(3a+2)

3. 9p*-q*-12p-4q
=-(3p-q)(3p+q)4(3p+q)
=-4(3p-q)(3p+q)(3p+q)

4. m(x+y)*-4m(x-y)*
=m(x+y)^2-4m(x-y)(x+y)
=(x+y)[m(x+y)-4m(x-y)]
=(x+y)(mx+my-4mx+4my))
=(x+y)(5my-3mx)
=m(x+y)(5y-3x)

2007-11-27 00:12:13 補充：
5. x*y(4次方)-16x*=(xy^2)^2-(4x)^2=(xy^2-4x)(xy^2 4x)=x^2(y^2-4)(y^2 4)=x^2(y-4)(y 4)(y^2 4)6. 18a* 15b-50b*-9a=18a^2-9a 15b-50b^2=9a(2a-1) 5b(3-10b)=(9a 5b)(3-10b)(2a-1)

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