Answer: z = 3
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Step-by-step explanation:
I'll use the substitution method to solve this system of equations.
Solve the third equation for z
2x+z = 5
z = 5-2x
Then solve the second equation for y
x+2y = 5
2y = 5-x
y = (5-x)/2
y = -0.5x+2.5
Plug each of these into the first equation so we can solve for x.
x+y+z = 6
x+(-0.5x+2.5)+(5-2x) = 6
-1.5x+7.5 = 6
-1.5x = 6-7.5
-1.5x = -1.5
x = (-1.5)/(-1.5)
x = 1
Let's use this to find y and z
y = -0.5x+2.5 = -0.5*1+2.5 = 2
z = 5-2x = 5-2*1 = 3
Therefore,
x = 1
y = 2
z = 3
Or we can write it like this: (x,y,z) = (1,2,3)
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Check:
Plug these values into equation 1 and simplify
x+y+z = 6
1+2+3 = 6
6 = 6
We get the same thing on both sides.
This confirms equation 1.
Repeat for equation 2.
x+2y = 5
1+2*2 = 5
1+4 = 5
5 = 5
This confirms equation 2.
Lastly, plug those values into equation 3
2x+z = 5
2*1+3 = 5
2+3 = 5
5 = 5
Equation 3 is confirmed.
All three equations are true when (x,y,z) = (1,2,3). The solution is fully confirmed.