Respuesta :

Answer:

  • (- 5, 9)

Step-by-step explanation:

Given system of equations

  • - 2x - y = 1
  • - 4x - y = 11

Express the first equation as

  • y = - 2x - 1

Substitute the value of y into second equation

  • - 4x - (- 2x - 1) = 11

Solve for x

  • - 4x + 2x + 1 = 11
  • - 2x + 1 = 11
  • - 2x = 10
  • 2x = - 10
  • x = - 5

Find the value of y

  • y = - 2(- 5) - 1 = 10 - 1 = 9

Answer:

(-5, 9)

Step-by-step explanation:

Given system of linear equations:

[tex]\begin{cases}-2x-y=1\\-4x-y=11\end{cases}[/tex]

To solve by substitution, use arithmetic operations to isolate y in Equation 1:

[tex]\implies -2x-y=1[/tex]

[tex]\implies -2x-y+y=1+y[/tex]

[tex]\implies -2x=1+y[/tex]

[tex]\implies -2x-1=1+y-1[/tex]

[tex]\implies y=-2x-1[/tex]

Substitute the expression for y into Equation 2 and solve for x:

[tex]\implies -4x-(-2x-1)=11[/tex]

[tex]\implies -4x+2x+1=11[/tex]

[tex]\implies -2x+1=11[/tex]

[tex]\implies -2x+1-1=11-1[/tex]

[tex]\implies -2x=10[/tex]

[tex]\implies -2x \div -2=10 \div -2[/tex]

[tex]\implies x=-5[/tex]

Substitute the found value of x into one of the equations and solve for y:

[tex]\implies -2(-5)-y=1[/tex]

[tex]\implies 10-y=1[/tex]

[tex]\implies 10-y+y=1+y[/tex]

[tex]\implies 10=1+y[/tex]

[tex]\implies 10-1=1+y-1[/tex]

[tex]\implies y=9[/tex]

Therefore, the solution to the given system of linear equations is (-5, 9).

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