Math help Please?

Question

I cant seem to isolate a variable to get an answer please someone help me go thru this

x-2y+3z=7
2x+y+5z=17
3x-4y-2z=1

Answer 1

-2x+4y-6z=-14 (1)*2
2x+y+5z=17 (2)
adding
5y-z=3.....(4)
-3x+6y-9z=-21 (1)*-3
3x-4y-2z=1 (3)
adding
2y-11z=-20 (5)
-55y+11z=-33 (4)*-11
adding
-53y=-53
y=1
sub in 5y-z=3
5-z=3
-z=-2
z=2
sub y and z in (1)
x-2+6=7
x=3
the solution set is (3,1,2)

Answer 2

Starting with the first one, rearrange to x = 7 + 2y - 3z. Plug into the second equation: 2(7 + 2y - 3z) + y + 5z = 17. Distribute: 14 + 4y - 6z + y + 5z = 17. Combine like terms: 14 + 5y - z = 17. Subtract 14: 5y - z = 3. Rearrange to z = 5y - 3. Now plug that into the first rearranged equation: x = 7 + 2y - 3(5y - 3) = 7 + 2y -15y + 9. Combine like terms: x = 16 - 13y. Now you have x and z in terms of y.

Now plug these values into an equation. It doesn't matter which one. We'll use the third one. 3(16 - 13y) - 4y - 2(5y - 3) = 1. Distribute: 48 - 39y - 4y - 10y + 6 = 1. Combine: 54 -53y = 1. Subtract 54: -53y = -53. Divide by -53: y = 1.

Now go back and plug y = 1 into your equations for x and z. x = 16 - 13 = 3. z = 5 - 3 = 2.

Finally, check your work. The following should be true:

3 - 2*1 + 3*2 = 7. Check.
2*3 + 1 + 5*2 = 17. Check.
3*3 - 4 - 2*2 = 1. Check.

So that's the right answer. x = 3, y = 1, z = 2.

Answer 3

you cant isolate a variable? how?

take that first line
add 2y and subtract 3z from the left side and you get
x=2y-3z+7
there ya go, an isolated variable

Answer 4

I bet you that you could multiply the top one by two,
the middle one by four,
and keep the bottom one the same, then you could get rid of the y's.