Question

Systems with3 VARIABLES CHOOSE TWO EQUATIONS in which you can easily eliminate a variable. Let’s call this new equation after the elimination Equation A.5x - 3y +8z = -599x - 4 y -z = -605x + 2 y +4z = -47

Answer 1

x=-7 y =0 z=-3

Starting from this Linear System

5x - 3y +8z = -59

9x - 4 y -z = -60 ⇒ -z = -60 +4y -9x

5x + 2 y +4z = -47

A) 5x - 3y +8z = -59 Multiply by 2

5x + 2 y +4z = -47 Multiply by 3

10x -6y +24z =-118

15x+6y+12z=-141

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25x +36z =-259 y=0

25x +36z = -259

9x - 4 y -z = -60 Plugging in the 2nd equatio the y=0

5x -3y +8z = -59

9x -4(0) -z = -60

5x +8z = -59

9x -z = -60 x8

5x +8z = -59

72x -8z =-480

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77x=-539

x=-7

5(-7)+ 2 (0) +4z = -47

-35+0+4z= -47

4z =-47 +35

4z = -12

z=-3