solve the following system of equations

Question

3x+3y+2z=-5 ,

x + y + 3z = -4 ,

2x+2y+5z =-7

Answer 1

Given that system of equations are 3x + 3x +2z = -5 ==> 1

                                                          x + y + 3z = -4 ==> 2

                                                         2x + 2y + 5z = -7 ==> 3

 Solve equation 1 and 2

3x + 3x +2z = -5 ==> 1

x + y + 3z = -4 ==> 2

Multiply equation 2 with 3

3x + 3x + 9z = -12 ==> 2

Substract equation 1 from 2

3x + 3x +2z = -5 ==> 1

3x + 3x + 9z = -12 ==> 2

(-)   (-)    (-)     (+)

                -7z= +7

                 -z = 1

                  z = -1

Substitute the value of z in equation 1

3x + 3x +2z = -5 ==> 1

3x + 3x +2(-1) = -5

3x + 3y - 2 = -5

3x + 3y = -5 + 2

3x + 3y = -3

Take common 3 from both side and cancel common terms

x + y = -1

It can not be solved further

Therefore x = -1 - y

x = -(1 + y)