Question

PLEASE HELPP (:
If you were to use the substitution method to solve the following system, choose the new system of equations that would result if x was isolated in the first equation. x-6y+3z=0 2x-5y+8z=7 x+7y-4z=13

Answer 1

plug in x= 6y-3z in eqns 2 and 3 in place of x to get 2 eqns in y and z only

Answer 2

x-6y+3z=0..........................1

2x-5y+8z=7........................2

x+7y-4z=13.........................3

Take eq 1
x= 6y-3z
sub this in equation 2 and 3

2( 6y-3z)-5y+8z=7..................2
6y-3z +7y-4z=13.....................3

simplify
12y-6z-5y+8z=7
then it be
7y+2z=7................2 multiplying by 7
13y-7z=13..............3 multiplying by 2

49y+14z=49 .............2
26y-14z=26...............3

adding both equations to each other to get
75 y = 75
then y=1

sub value of y in 2 or 3 to get
7+2z=7
2z=0
z= zero

sub z= zero , y =1 , in eq 1
x= 6y-3z
x=6

Hope I'm right . and You are welcome .. regards