Question

Y = 3x -1,2x + y = 9;​

Answer 1

Объяснение:

Если у=3х-1, то

2х+у=9 мы можем записать 2х+3х-1=9

5х=9+1

х=10÷5

х=2

у=3х-1

у=6-1

у=5

Answer 2

To solve the system of equations:

1. Y = 3x - 1
2. 2x + y = 9

You can use the substitution method or the elimination method. I'll demonstrate both methods.

Method 1: Substitution

1. Solve equation (1) for y:

   Y = 3x - 1

2. Substitute the expression for y from equation (1) into equation (2):

   2x + (3x - 1) = 9

3. Now, solve for x:

   2x + 3x - 1 = 9

   5x - 1 = 9

   5x = 10

   x = 10 / 5

   x = 2

4. Now that you have found the value of x, substitute it back into equation (1) to find y:

   Y = 3x - 1 Y = 3(2) - 1 Y = 6 - 1 Y = 5

So the solution to the system of equations is:

x = 2 y = 5

Method 2: Elimination

1. Start with the two equations:

   Y = 3x - 1 2x + y = 9

2. Rearrange equation (1) to make y the subject:

   y = 3x - 1

3. Now, add the two equations together to eliminate y:

   (2x + y) + (-(3x - 1)) = 9 - 1

   2x + y - 3x + 1 = 8

4. Combine like terms:

   (2x - 3x) + (y + 1) = 8

   -x + (y + 1) = 8

5. Move the -x term to the other side of the equation:

   y + 1 = 8 + x

6. Subtract 1 from both sides:

   y = 8 + x - 1

   y = 7 + x

7. Now you have a new equation for y. You can substitute this equation into equation (2) to solve for x:

   2x + (7 + x) = 9

8. Combine like terms:

   2x + 7 + x = 9

   3x + 7 = 9

9. Subtract 7 from both sides:

   3x = 2

10. Finally, divide by 3 to find x:

x = 2/3

Now that you have the value of x, you can substitute it back into the equation for y:

y = 7 + x y = 7 + 2/3

To make the fractions easier to work with, you can express 7 as a fraction with a common denominator:

y = 21/3 + 2/3

Now, add the fractions:

y = (21 + 2) / 3 y = 23/3

So, using the elimination method, the solution is:

x = 2/3 y = 23/3