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X – 7y + 3z = 17
5х + 2y – 2z = -57
3х – 10у - z = -11

1 Answer

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Final answer:

To solve the system of equations, use the method of elimination to eliminate a variable in each step until left with a system of two equations. Then solve for one variable and substitute back to find the values of the other variables.

Step-by-step explanation:

To solve the system of equations:

x - 7y + 3z = 17

5x + 2y - 2z = -57

3x - 10y - z = -11

we can use the method of elimination:

  • Multiply the first equation by 5 and the second equation by -3 to eliminate x:
  • 5x - 35y + 15z = 85
  • -15x - 6y + 6z = 171
  • Add the two equations together to eliminate x:
  • -41y + 21z = 256
  • Multiply the second equation by 3 and the third equation by 5 to eliminate x:
  • 15x - 50y - 5z = -165
  • 15x - 30y - 3z = 165
  • Add the two equations together to eliminate x:
  • -80y - 8z = 0
  • Now we have a system of two equations:
  • -41y + 21z = 256
  • -80y - 8z = 0
  • Multiply the second equation by -41 to eliminate y:
  • 3280y + 328z = 0
  • Add the two equations together to eliminate y:
  • 349z = 256
  • Divide by 349 to solve for z:
  • z ≈ 0.735
  • Substitute z back into one of the equations to solve for y:
  • -80y - 8(0.735) = 0
  • y ≈ -0.735
  • Finally, substitute the values of y and z back into one of the original equations to solve for x:
  • x - 7(-0.735) + 3(0.735) = 17
  • x ≈ 10.307

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