Question 105836This question is from textbook
: i need to solve -2x+y+z=-2
5x+3y+3z=71
4x-2y-3z=1
i have to solve for x,y, and z PLEASE HELP!!!! This question is from textbook
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Eq1: -2x + y + z = -2
Eq2: 5x + 3y + 3z = 71
Eq3: 4x - 2y - 3z = 1
:
We can solve it by using elimination:
using equations 2 & 3
5x + 3y + 3z = 71
4x - 2y - 3z = 1
-----------------adding eliminates z
9x + 1y + 0z = 72
9x + y = 72
:
Using equations 1 and 3:
Mult eq 1 by 3 and add it to equation 3
:
-6x + 3y + 3z = -6
4x - 2y - 3z = 1
-----------------adding eliminates 3 again
-2x + 1y + 0z = -5
-2x + y = -5
:
We have two 2 unknown equations to work with now:
Subtract the 2nd one from the 1st one.
9x + y = 72
-2x +y = -5
--------------subtracting eliminates y, find x
11x + 0y = 77
x = 77/11
x = 7
:
Use 9x + y = 72 to find y
9(7) + y = 72
63 + y = 72
y = 72 - 63
y = 9
:
I'm sure you can find a way to find z. Check all 3 solutions in one of the
original equations
