Solve the system 5x 10y 3z 29 x 5y z 0 10x y z 21 Sel

Solve the system. {5x - 10y + 3z = 29 x + 5y - z =0 10x - y - z =21 Select the correct choice below and, if necessary, fill in the answer box.

a) As shortcut, just try substituting the cordinates (3,1,8) in all 3 equation. Does it satisfy all the equation?

Yes. therefore, this is answer. We will also do it the harder way:

5x-10y+3z=29......1

x+5y-z=0..............2

10x-y-z=21.......... 3

Subtracting 2 from 3, 2-3 we have 9x-6y=21=> 3x-2y=7......4

triple equ 2 and add to 1=>8x+5y=29......5

Solving equ 4 and 5 now, 5*Equ4 + 2*Equ5 we have , 31x = 35+58 = 93, x=3 substituting this in equ4, y=1 and in equ3, we have z=8