Question

- Решите уравнение:
1) (х - 4)(х + 2) - (х - 5)(х + 6) = -х;
2) 12х2 - (3х - 4)(4х + 1) = 19;
3) (3x+5)(2x + 1) = (6х + 5)(х - 3) + 7;
4) (х + 1)(х-2) - (х + 5)(х + 4) = -2.​

Answer 1

1) (х-4)(х+2)-(х-5)(х+6)=-х

(x^2+2x-4x-8)-(x^2+6x-5x-30)+x=0

x^2+2x-4x-8-x^2-x+30+x=0

2x-4x-8+30=0

-2x+22=0

2x=22

x=22/2

x=11

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2) 12х^2-(3х-4)(4х+1)=19

12x^2-(12x^2+3x-16x-4)-19=0

12x^2-12x^2-3x+16x+4-19=0

13x-15=0

13x=15

x=15/13

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3) (3x+5)(2x+1)=(6х+5)(х-3)+7

6x^2+3x+10x+5=6x^2-18x+5-15+7

13x+5=-13x-8

13x+13x=-8-5

26x=-13

x=-13/26

x=-1/2

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4) (х+1)(х-2)-(х+5)(х+4)=-2

(x^2-2x-x+2)-(x^2+4x+5x+20)+2=0

x^2-2x-x+2-x^2-4x-5x-20+2=0

-12x-16=0

-12x=16

x=-16/12

x=-4/3