Решите уравнения:

1. (x+3) (x-4) = - 12

2.18 - (x-5) (x-4) = - 2

3. (3x-1) ²=1

4.5x + (2x+1) (x-3) = 0

5. (2x+3) (3x+1) = 11x+30

6. x²-5 = (x-5) (2x-1)

1. (x+3) (x-4) = - 12

x^2+3x-4x-12=-12

x^2-x=0

x=0 или x-1=0

x=1

2.18 - (x-5) (x-4) = - 2

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

18-x^2+9x-18=0

-x^2+9x=0

x=0 или - x+9=0

x=9

3. (3x-1) ²=1

9x^2-6x+1=1

9x^2-6x=0

3x=0 или 3x-2=0

x=2/3

4.5x + (2x+1) (x-3) = 0

5x + (2x^2+x-6x-3) = 0

2x^2-3=0

x^2=3/2

5. (2x+3) (3x+1) = 11x+30

6x^2+9x+2x+3-11x-30=0

6x^2-27=0

x^2=27/6

x^2=9/2 (+-3/корень из 2)

6. x²-5 = (x-5) (2x-1)

x^2-5=2x^2-10x-x+5

x^2-11x+10=0

D=121-40=81

x1 = (11-9) / 2=1

x2 = (11+9) / 2=10