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Zagornaya2015

03 марта 2014 г., 21:31:07 (10 лет назад)

382

1) (x+5)^2-x^2=x-2

x^2+10x+25-x^2-x+2=0

9x+27=0

x=-3

2) (6-x)^2-16=x^2-2x

36-12x+x^2-16-x^2+2x=0

-10x+20=0

-10x=-20

10x=20

x=2

3) (3x+1)^2-(3x-1)^2=x+5

9x^2+6x+1-(9x^2-6x+1)-x-5=0

6x+6x-x-5=0

11x-5=0

11x=5

x=5/11

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

(2y-1)(2y-1)^2+(2y+1)(2y+1)^2=y(1+16y^2)+2

8y^3-8y^2+2y-4y^2+4y-1+(2y+1)(4y^2+4y+1)=y(1+16y^2)+2

8y^3-12y^2-6y+1+(8y^3+8y^2+2y+4y^2+4y+1=y(1+16y^2)+2

8y^3+6y+1+8y^3+6y+1=y(1+16y^2)+2

16y^3+12y+2=y(1+16y^2)+2

16y^2+12y+2=y+16y^3+2

16y^3+12y+2-y-16y^3-2=0

12y-y=0

11y=0

y=0

383

1) a^2+a/a^2-1=abx/ab-b

(a^2+a)(ab-b)=(a^2-1)(abx)

a^3b-ba^2+ba^2-ab=a^3bx-abx

a^3b-ab=a^3bx-abx

x(a^3b-ab)=a^3b-ab

x=a^3b-ab/a^3b-ab

x=1

2) 6a^3-6/a^2+a+1=(a-1)x/18

18(6a^3-6)=(a^2+a+1)(a-1)x

(a^3-1)x=108a^3-108

x=108a^3-108/a^3-1

x=108(a^3-1)/a^3-1

x=108

3) ab+3/21b^3+21=7x/5b^2-5b+5

49x(b^3+1)=(b+1)(5b^2-6b+5)

49x(b^3+1)=5b^3-5b^2+5b+5b^2-5b+5

49x(b^3+1)=5b^3+5

49x(b^3+1)=5(b^3+1)

49x=5

x=5/49

4) a^2b-a/1-a^2b^2=6ax/18+18ab

a^2b-a/1-a^2b^2=6ax/18(1+ab)

a^2b-a/1-a^2b^2=ax/3(1+ab)

ax(1-a^2b^2)=3(1+ab)(a^2b-a)

x(a-a^3b^2)=3(a^2b-a+a^3b^3-a^2b)

x=3(a^3b^3-a)/a-a^3b^2