Question 795005
{2x-y=9
{x-2z=-3
{2y+3z=15
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{2x-y=9
{x-2z= -3
{2y+3z=15
Modify::
y = 2x-9
z = (x+3)/2
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Substitute into 2y + 3z = 15 and solve for "x":
2(2x-9) +3(x+3)/2 = 15
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4(2x-9) + 3x+9 = 30
8x - 36 + 3x + 9 = 30
11x - 27 = 30
11x = 57
x = 5 2/11
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Solve for "y" and for "z"::
y = 2(57/11)-(99/11)
y = 15/11
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Solve for "z"::z = (x+3)/2
z = [57/11 + 33/11)/2 = 45/11
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Cheers,
Stan H.
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