SOLUTION: can someone please help me with this problem: Solve the system of equations. If the system is dependent, express solutions in terms of the parameter z. -2x + y + 4z = 10 -7x

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: can someone please help me with this problem: Solve the system of equations. If the system is dependent, express solutions in terms of the parameter z. -2x + y + 4z = 10 -7x      Log On


   



Question 164582This question is from textbook
: can someone please help me with this problem:
Solve the system of equations. If the system is dependent, express solutions in terms of the parameter z.
-2x + y + 4z = 10
-7x + 4y - 3z = 7
a. (19z - 33, 34z - 56, z)
b. (33 - 43z, 56 - 34z, z)
c. (-33 + 43z, 10 - 2x + 4z, z)
d. (-33 + 43z, 10 + 2x - 4z, z)
This question is from textbook

Answer by Edwin McCravy(20054) About Me  (Show Source):
You can put this solution on YOUR website!

-2x +  y + 4z = 10
-7x + 4y - 3z =  7 

Leave only the x and y terms on the left:

 -2x +  y = -4z + 10
 -7x + 4y =  3z +  7

Eliminate y by multiplying the first equation
by -4 and adding to the second:

  8x - 4y = 16z - 40
 -7x + 4y =  3z +  7 
----------------------
   x      = 19z - 33

Eliminate x by multiplying the first equation
by -7 and the second by +2 and adding them:

 14x - 7y = 28z - 70
-14x + 8y =  6z + 14
--------------------
        y = 34z - 56

Therefore (x, y, z) = (19z-33, 34z-56, z)  choice a

Edwin