Help me please с 2 номера

+ 0 -

Ymv0102

09 авг. 2013 г., 13:35:06 (10 лет назад)

#2
a) (х-4)^2-(x+1)(x+2)=x^2-8x+16-x^2-3x-2=-11x+14
b) 5(a+b)^2-10ab=5a^2+10ab+5b^2-10ab=5(a^2+b^2)

#3
a) 9y^2-25=(3y-5)(3y+5)
b) 4a-a^3=a(4-a^2)=a(2-a)(2+a)
c) -2a^2+4ac-2c^2=-2(a^2+2ac+c^2)=-2(a+c)^2

#4
(2b+b^2)^2+b^2(5-b)(5+b)-4b(b^2-3)=b^2(4+4b+b^2)+b^2(25-b^2)-4b*b^2+12b=
=b^2(4+4b+b^2+25-b^2-4b)+12b=29b^2+12b

#5

a) 16-(y+1)^2=(4-y-1)(4+y+1)=(3-y)(y+5)

b) 1/27*a^3-x^3=(1/3*a)^3-x^3=(1/3*a-x)(1/9*a^2+1/3*ax+x^2)

c) a^4 -16b^4=(a^2-4b^2)(a^2+4b^2)=(a-2b)(a+2b)(a^2+4b^2)

d) 3c-c^2-3a+a^2=3(c-a)-(c^2-a^2)=3(c-a)-(c+a)(c-a)=(3-c-a)(c-a)