1)

[tex]2 {x }^{2} - 5x - 7 = 0[/tex]

[tex]2 \times ( - 1) {}^{2} - 5 \times ( - 1) - 7 = 0 \\ 2 \times 1 + 5 - 7 = 0 \\ 2 + 5 - 7 = 0 \\ 7 - 7 = 0 \\ 0 = 0[/tex]

[tex]2 \times (3.5) {}^{2} - 5 \times 3.5 - 7 = 0 \\ 2 \times 12.25 - 17.5 - 7 = 0 \\ 24.5 - 24.5 = 0[/tex]

2)

[tex]5 {x}^{2} + 2x - 3 = 0[/tex]

[tex]5 \times ( - 1) {}^{2} + 2 \times ( - 1) - 3 = 0 \\ 5 \times 1 - 2 - 3 = 0 \\ 5 - 5 = 0 \\ 0 = 0[/tex]

[tex]5 \times (3.5) {}^{2} + 2 \times 3.5 - 3\neq0 \\ 5 \times 12.25 + 7 - 3\neq0 \\ 61.25 + 4\neq0 \\ 65.25\neq0[/tex]

3)

[tex]4 {x}^{2} + 3x - 1 = 0[/tex]

[tex]4 \times ( - 1) {}^{2} + 3 \times ( - 1) - 1 = 0 \\ 4 \times 1 - 3 - 1 = 0 \\ 4 - 4 = 0 \\ 0 = 0[/tex]

[tex]4 \times (3.5) {}^{2} + 3 \times 3.5 - 1 \neq0 \\ 4 \times 12.25 + 10.5 - 1\neq0 \\ 49 + 9.5\neq0 \\58.5\neq0[/tex]

4)

[tex]6 {x}^{2} + 7x - 5 = 0[/tex]

[tex]6 \times ( - 1) {}^{2} + 7 \times ( - 1) - 5\neq0 \\ 6 \times 1 - 7 - 5\neq0 \\ 6 - 12\neq0 \\ - 6\neq0[/tex]

[tex]6 \times ({3.5)}^{2} + 7 \times 3.5 - 5\neq0 \\ 6 \times 12.25 + 24.5 - 5 \neq0 \\ 73.5 + 19.5\neq0 \\ 93\neq0[/tex]

Ответ: 1)