Solve the System: Find x and y in -5x + y = 8 and 3x - 2y = 11 Using Substitution

Question

Find the value of x and and band the substitution method.

{5x+y=83x2y=11 \begin{cases} -5x+y=8 \\ 3x-2y=11 \end{cases}

Video Solution

Step-by-Step Solution

To solve this system of equations using the substitution method, we follow these steps:

  • Step 1: Solve for one of the variables in terms of the other using the first equation 5x+y=8 -5x + y = 8 .
    • We solve for y y :

    y=5x+8 y = 5x + 8

  • Step 2: Substitute the expression for y y from Step 1 into the second equation 3x2y=11 3x - 2y = 11 .
  • 3x2(5x+8)=11 3x - 2(5x + 8) = 11

  • Step 3: Simplify and solve for x x .
  • Simplify the substitution:

    3x10x16=11 3x - 10x - 16 = 11

    7x16=11 -7x - 16 = 11

    Add 16 to both sides:

    7x=27 -7x = 27

    Divide by -7:

    x=277 x = -\frac{27}{7}

  • Step 4: Substitute x x back into the expression for y y from Step 1.
  • y=5(277)+8 y = 5\left(-\frac{27}{7}\right) + 8

    Simplify:

    y=1357+567 y = -\frac{135}{7} + \frac{56}{7}

    y=1357+567=797 y = -\frac{135}{7} + \frac{56}{7} = -\frac{79}{7}

Therefore, the solution to the system is x=277 x = -\frac{27}{7} and y=797 y = -\frac{79}{7} .

Answer

x=277,y=797 x=-\frac{27}{7},y=-\frac{79}{7}