Question

26.
1) x²-3x = 0;
3) 0,7x-1,4x² = 0;
2) 5x + 2x² = 0;
4) 1/7x2-3 1/7x2 = 0​

Answer 1

Ответ:

1) x = 0 або x - 3 = 0, тобто x = 3
2) x = 0 і x = -5/2
3) x = 0 і x = 0.5
4) x = 0

Объяснение:

1) x² - 3x = 0

x - спільний член

x(x - 3) = 0

x = 0 або x - 3 = 0, тобто x = 3

2) 5x + 2x² = 0

x(5 + 2x) = 0

a) x = 0

b) 5 + 2x = 0

2x = -5

x = -5/2

знову два розв'язки: x = 0 і x = -5/2

3) 0.7x - 1.4x² = 0

x(0.7 - 1.4x) = 0

a) x = 0

b) 0.7 - 1.4x = 0

-1.4x = -0.7

x = -0.7 / (-1.4)

x = 0.5

x = 0 і x = 0.5

4) (1/7)x^2 - 3(1/7)x^2 = 0

(1/7 - 3/7)x^2 = 0 - спростили вираз, спiльний множник 1/7

a) (1/7 - 3/7)x^2 = 0

-2/7x^2 = 0

x^2 = 0

x = 0

b) (1/7 - 3/7)x^2 = 0

-2/7x^2 = 0

x = 0