Question

3х-у=-1 и -х+2у=7 помогите решить систему

Answer 1

3х-у=-1
-х+2у=7
из 1
3x+1=y
поставим на 2
-x+2(3x+1)=7
-x+6x+2=7
5x=7-2
5x=5
x=1
y=3*1+1=4
ответ: (1;4)

Answer 2

Solving the System of Equations

To solve the system of equations 3x - y = -1 and -x + 2y = 7, we can use the substitution method or the elimination method. Let's use the elimination method to solve this system.

First, we'll multiply the second equation by 3 to make the coefficients of y in both equations the same. This will allow us to eliminate y when we add the equations together.

Multiplying the second equation by 3: - Original equation: -x + 2y = 7 - Multiply by 3: -3x + 6y = 21

Now, we'll add the modified second equation to the first equation: - 3x - y = -1 - -3x + 6y = 21 - Adding the equations: 5y = 20

Now, we can solve for y: - 5y = 20 - y = 4

Next, we'll substitute the value of y back into one of the original equations to solve for x. Let's use the first equation 3x - y = -1: - 3x - 4 = -1 - 3x = 3 - x = 1

So, the solution to the system of equations is: - x = 1 - y = 4

Conclusion

The solution to the system of equations 3x - y = -1 and -x + 2y = 7 is: - x = 1 - y = 4