Chapter 9.2, Problem 39WE

To determine

To find: The solution of the given equations by using substitution method.

Answer to Problem 39WE

The solution of the given equations by using substitution method is $x=20,y=60\text{ and }z=100$

Explanation of Solution

Given information:

The given equations are,

  $\begin{array}{l}x+y+z=180\\ y=3x\\ z=5x\end{array}$

Substitute $3x$ for $y$ and $5x$ for $z$ in the Equation :

  $\begin{array}{l}x+y+z=180\\ x+3x+5x=180\\ 9x=180\\ x=20\end{array}$

For the value of $y$ and $z$ , Substitute 20 for $x$

  $\begin{array}{l}y=3x\\ y=3\left(20\right)\\ y=60\end{array}$

  $\begin{array}{l}z=5x\\ z=5\left(20\right)\\ z=100\end{array}$

Thus, the solution of the given equations by using substitution method is $x=20,y=60\text{ and }z=100$