2х-7х+3=0 5Х-3Х-2=0 2Х-5Х+3=0 Х+3Х-1=0

Решим уравнения с подмогою дискриминанта.

1) D = 7² 4 * 2 * 3 = 49 24 = 25 = 5².

x₁ = (7 5) / (2 * 2) = 2/4 = 0,5;

x₂ = (7 + 5) / (2 * 2) = 12/4 = 3.

Ответ: х₁ = 0,5; х₂ = 3.

2) D = 3² 4 * 5 * (- 2) = 9 + 40 = 49 = 7².

x₁ = (3 7) / (2 * 5) = - 4/10 = - 0,4;

x₂ = (3 + 7) / (2 * 5) = 10/10 = 1.

Ответ: х₁ = - 0,4; х₂ = 1.

3) D = 5² 4 * 2 * 3 = 25 24 = 1.

x₁ = (5 - 1) / (2 * 2) = 4/4 = 1;

x₂ = (5 + 1) / (2 * 2) = 6/4 = 3/2 = 1,5.

Ответ: х₁ = 1; х₂ = 1,5.

4) D = 3² 4 * 1 * (- 1) = 9 + 4 = 13.

x₁ = (- 3 - 13) / (1 * 2) = (- 3 - 13)/2;

x₂ = (- 3 + 13) / (1 * 2) = (- 3 + 13)/2.

Ответ: х₁ = (- 3 - 13)/2; х₂ = (- 3 + 13)/2.