Q 62 - Intermediate Algebra

Question

In the following exercise, solve the systems of equations by elimination.

$\left\{\begin{array}{l}x-4y=-1\\ -3x+12y=3\end{array}\right.$

Step-by-Step Solution

Answer

The given system has infinitely many solutions.

Step 1. Given information

The given linear equations are : 

$$\begin{gathered} x-4y=-1 \\ -3x+12y=3 \end{gathered}$$

Step 2. Calculating the value of y

To calculate the value of $y$, we have to eliminate the $x$ term. For which we will do the following changes in the equation, so that $x$ term can be easily eliminated.

Multiply first equation by 3

$$\begin{gathered} 3\left(x-4y=-1\right) \\ 3x-12y=-3 \end{gathered}$$

 now, the equations are 

$$\begin{gathered} 3x-12y=-3 \\ -3x+12y=3 \end{gathered}$$

now simply add the equations

$3x-12y=-3-3x+12y=30=0$

This means that the above equation is satisfied for all the values of $x$ and $y$.