Question

2х-(7х-5)=35;; 7х-(х+3)=3(2х-1);; 6х+7/7+х=90+3х/5 / это дробь​

Answer 1

2x-(7x-5)=35

2x-7x+5=35

2x-7x=35-5

-5x=30

x=30:(-5)

x=-6

Ответ:x=-6

7x-(x+3)=3(2x-1)

7x-x-3=6x-3

7x-x-6x=-3+3

x=0

Ответ:x=0

6x+7/7+x=90+3x/5

6x+1+x=90+0,6x

6x+x-0,6x=90-1

6,4x=89

x=89:6,4

x=13,90625

Ответ:x=13,90625

Answer 2

1) ответ: -6

2) ответ: 0

3) ответ: -7

Answer 3

To solve the given equations, let's take them one by one:

1. 2х - (7х - 5) = 35

Step 1: Remove the parentheses using the distributive property. 2х - 7х + 5 = 35

Step 2: Combine like terms (2х and -7х). -5х + 5 = 35

Step 3: Isolate the variable by moving the constant term to the other side of the equation. -5х = 35 - 5 -5х = 30

Step 4: Solve for х by dividing both sides by -5. х = 30 / -5 х = -6

So the solution for the first equation is х = -6.

2. 7х - (х + 3) = 3(2х - 1)

Step 1: Remove the parentheses using the distributive property. 7х - х - 3 = 6х - 3

Step 2: Combine like terms (7х and -х). 6х - 3 = 6х - 3

Step 3: Now, observe that both sides of the equation are the same. This indicates that the equation has infinitely many solutions. In other words, for any value of х, the equation will hold true.

So, the second equation has infinitely many solutions.

3. (6х + 7) / (7 + х) = (90 + 3х) / 5

To solve this equation, we'll first clear the fractions by multiplying both sides by the common denominator (5 * (7 + х)):

5 * (7 + х) * [(6х + 7) / (7 + х)] = 5 * (7 + х) * [(90 + 3х) / 5]

Step 1: Cancel out common terms on both sides. 6х + 7 = (7 + х) * (90 + 3х)

Step 2: Expand the right side using the distributive property. 6х + 7 = 630 + 90х + 3х^2

Step 3: Move all terms to one side to set the equation to zero. 3х^2 + 90х + 7 - 630 = 0

Step 4: Simplify further. 3х^2 + 90х - 623 = 0

Now, this is a quadratic equation in the form of ax^2 + bx + c = 0, where a = 3, b = 90, and c = -623. To solve this equation, you can use the quadratic formula:

x = (-b ± √(b^2 - 4ac)) / 2a

Substitute the values: x = (-(90) ± √(90^2 - 4 * 3 * (-623))) / (2 * 3)

Calculate the discriminant: x = (-90 ± √(8100 + 7476)) / 6 x = (-90 ± √15576) / 6 x = (-90 ± 124.7) / 6

Now find the two possible solutions for x:

1. x = (-90 + 124.7) / 6 x = 34.7 / 6 x ≈ 5.78

2. x = (-90 - 124.7) / 6 x = -214.7 / 6 x ≈ -35.78

So, the solutions for the third equation are approximately x = 5.78 and x = -35.78.