Question

0,4x + 4,6 = 0,7x − 0,4; – 3 · (2 – 15x) = – 6; 2,1 · (4 – 6y) = – 42;

Answer 1

Ответ:

0,4x+4,6=0,7x-0,4

0,4x-0,7x=-0,4-4,6

-0,3x=-5

x=16,6

-3•(2-15x)=-6

2-15x=2

-15x=0

x=0

2,1•(4-6y)=-42

4-6y=-20

-6y=-20-4

-6y=-25

y=4

Answer 2

Let's solve the given equations one by one:

1. 0.4x + 4.6 = 0.7x - 0.4

To solve this equation, we'll first eliminate the decimals by multiplying the entire equation by 10 to get rid of the decimal points:

10 * (0.4x + 4.6) = 10 * (0.7x - 0.4)

4x + 46 = 7x - 4

Next, we'll group the x terms on one side and the constant terms on the other side:

7x - 4x = 46 + 4

3x = 50

Now, divide both sides by 3 to solve for x:

x = 50/3

So the solution to the first equation is x = 16.67 (rounded to two decimal places).

2. -3 * (2 - 15x) = -6

Let's simplify the left side of the equation:

-3 * 2 + 3 * 15x = -6

-6 + 45x = -6

Now, isolate the variable term:

45x = 0

Divide both sides by 45 to solve for x:

x = 0

Therefore, the solution to the second equation is x = 0.

3. 2.1 * (4 - 6y) = -42

Again, we'll eliminate the decimal by multiplying both sides by 10:

10 * (2.1 * (4 - 6y)) = 10 * (-42)

21 * (4 - 6y) = -420

Now, distribute 21 on the left side:

84 - 126y = -420

Next, isolate the variable term:

-126y = -420 - 84

-126y = -504

Divide both sides by -126 to solve for y:

y = (-504) / (-126)

Simplifying the right side gives:

y = 4

Therefore, the solution to the third equation is y = 4.

To summarize:

1. x = 16.67
2. x = 0
3. y = 4