Question

|2х2-7х|-5=0срочно ​

Answer 1

Ответ:

х = - 1/7

х = 9/7 ( равно одна целая и две седьмых )

Пошаговое объяснение:

Тут не очень понятно, 2х2 - это два умножить на два, или два икс два, но я решу как два умножить на два минус семь икс, в любом случае, до 3го этапа всё правильно

1) |2х2-7х|-5=0

2) |2х2-7х|=5

3) 2х2-7х=5 или -(2х2-7х)=5

4-7х=5 - (4-7х)=5

-7х=5-4 -4+7х=5

-7х=1 7х=4+5

х= 1 : (-7) 7х=9

х= - 1/7 х=9/7

Answer 2

To solve the equation |2x2 - 7x| - 5 = 0, you can follow these steps:

1. Add 5 to both sides of the equation to isolate the absolute value expression:

|2x2 - 7x| = 5

2. Break the equation into two separate cases, one for when the expression inside the absolute value is positive and one for when it is negative. For the positive case:

2x2 - 7x = 5

3. Rearrange the equation into standard quadratic form:

2x2 - 7x - 5 = 0

4. Factor the quadratic equation:

(2x + 1)(x - 5) = 0

5. Solve for x by setting each factor equal to zero:

2x + 1 = 0 or x - 5 = 0

6. Solve for x in each equation:

2x + 1 = 0 -> x = -1/2

x - 5 = 0 -> x = 5

For the negative case, you need to change the sign of the expression inside the absolute value bars:

-(2x2 - 7x) = 5

7. Simplify by distributing the negative sign:

-2x2 + 7x = 5

8. Rearrange the equation into standard quadratic form:

-2x2 + 7x - 5 = 0

9. Solve for x using the quadratic formula:

x = (-b ± √(b2 - 4ac)) / 2a

where a = -2, b = 7, and c = -5. Plugging in these values, you get:

x = (-(7) ± √((7)2 - 4(-2)(-5))) / 2(-2)

x = (-(7) ± √(49 - 40)) / (-4)

x = (-(7) ± √9) / (-4)

x = (-7 ± 3) / (-4)

x = -1/2 or 5/2

So the solutions to the equation are x = -1/2, 5/2, and 5.