Question

решите уравнения 

а) 9y-y^2=0

б) -2x^2-4x=0

в) x^3-x^2=0

г) x^2-4=0

д) 4x^2-25=0

е) 1-z^2=0

з) 3z^2-75=0

Answer 1

a) y(9-y) = 0

y = 0

и 9-y = 0

-y = -9

y = 9

Ответ: 0 и 9

б) -2x^2 - 4x = 0

-2x(x + 2) = 0

-2x = 0      x+2 = 0

x = 0         x = -2

Ответ: 0 и -2

в)x^3 - x^2 = 0

x^2(x - 1) = 0

x = 0       x = 1

Ответ: 0 и 1

г)x^2 - 4 = 0

(x-2)(x+2) = 0

x = 2 и x = -2

Ответ: 2 и -2

д)4x^2 - 25 = 0

(2x-5)(2x+5) = 0

2x-5 = 0 и 2x+5 = 0

2x = 5        2x = -5

x = 2,5       x = -2,5

Ответ: 2,5 и -2,5

е)1-z^2 = 0

(1-z)(1+z) = 0

1-z = 0 и 1+z = 0

z = 1 и      z = -1

Ответ: -1 и 1

з)3z^2 - 75 = 0

3(z^2 - 25) = 0

3(z-5)(z+5) = 0

3<>0 и z = 5 и z = -5

Ответ: 5 и -5