# solve the following system of equations?

x+5z=30

5x+y=30

y-7z=-30

I am trying to find solutions to this problem. I can't figure it out. someone, please help???

### 2 Answers

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- Wayne DeguManLv 71 month ago
x + 5z = 30...(1)

5x + y = 30...(2)

y - 7z = -30...(3)

We can combine equation (1) and (2) to eliminate x, leaving another equation containing y and z.

i.e. 5(1) - (2) => 25z - y = 120...(4)

Now, (3) + (4) => 25z - 7z = 90

so, 18z = 90

i.e. z = 90/18 = 5

Using (3) we get, y - 7(5) = -30

so, y = 5

And, using (2) we get, 5x + 5 = 30

i.e. 5x = 25

so, x = 5

Hence, (x, y, z) => (5, 5, 5)

:)>

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- PinkgreenLv 71 month ago
x+5z=30------(1)

5x+y=30------(2)

y-7z=-30------(3)

(2)-(3)=>

5x+7z=60----(4)

5(1)-(4)=>

25z-7z=90

=>

18z=90

=>

z=5

x=5 from (1)

y=5 from (3)

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