SOLUTION: Need to see the steps in solving this linear equation (not by cramers rule)

Algebra ->  Linear-equations -> SOLUTION: Need to see the steps in solving this linear equation (not by cramers rule)       Log On


   

Question 668797: Need to see the steps in solving this linear equation (not by cramers rule)

Answer by ReadingBoosters(3246) About Me  (Show Source):
You can put this solution on YOUR website!
2x - 5y + 4z = 8
2x + y + z = -1
x -3y + 2z = 7
...
Multiply the last equation by -2
-2(x - 3y + 2z = 7)
-2x + 6y - 4z = -14
...
Add to the first equation
2x + -2x + -5y + 6y + 4z + -4z = 8 + -14
Combine like terms
highlight_green%28y+=+-6%29
...
Multiply the second equation by -1
-1(2x + y + z = -1)
-2x - y - z = 1
...
Add to the first equation
2x + -2x + -5y + -y + 4z + - z = 8 + 1
Combine like terms
-6y + 3z = 9
Substitute the value of y
-6(-6) + 3z = 9
3z = 9 - 36
3z = -27
highlight_green%28z=-9%29
...
Use value of y and z to solve for x
2x - 5(-6) + 4(-9) = 8
2x + 30 - 36 = 8
2x = 8 - 30 + 36
2x = 14
highlight_green%28x+=+7%29
...
Check
cartoon%282%287%29+-+5%28-6%29+%2B+4%28-9%29%2C%0D%0A14+%2B+30+-+36%2C%0D%0A8%29
cartoon%282%287%29+-+6+-+9%2C%0D%0A14+-+6+-+9%2C%0D%0A-1%29
cartoon%287+-+3%28-6%29+%2B+2%28-9%29%2C%0D%0A7+%2B+18+-+18%2C%0D%0A7%29
.....................
Delighted to help.
-Reading Boosters
Wanting for others what we want for ourselves.
www.MyHomeworkAnswers.com