Question

X+y-z=5 -x-4y-8z=6 3x+5y-4z=-20

Answer 1

Answer:

x = 24.48, y = -15.52, z = 3.95 to the nearest hundredth.

Step-by-step explanation:

 x+y-z=5             (a)

-x-4y-8z=6          (b)

3x+5y-4z=-20      (c)

Adding equations a and b:

-3y - 9z = 11       (d)

Now multiply equation b by 3:

-3x - 12y - 24z = 18        (e)

Adding  c and e:

-7y - 28z = -2      (f)  Multiply by 3 to give (g)

-3y - 9z = 11         (b)   Multiply by  -7 to give (h)

-21y - 84z = -6     (g)

21y + 63z = -77    (h)    Adding g and h:

-21z = - 83

z =  3.952

and y is found bt substituting in equation d:

-3y - 9(3.952) = 11

y = ( 11 + 9(3.952) / -3

= -15.52.

Now find x by substituting for y an z in equation a:

x - 15.52 - 3.952 = 5

x = 5 + 15.52 + 3.952

= 24.476.