Chapter 6, Problem 12MCQ

To determine

To solve: The given system of linear equation using substitution.

Answer to Problem 12MCQ

The solution of given system of equations is $x=3$ and $y=-12$ .

Explanation of Solution

Given information:

The given system of equations is

  $y=-4x$

  $6x-y=30$ .

Concept used:

In substitution expression for one variable from an equation is substituted in other. And the so obtained single variable equation is solved.

Calculations:

The given system of equation is

  $y=-4x$  ...... (1)

  $6x-y=30$  ...... (2)

Now, substituting expression for y from equation (1) into equation (2)

  $6x-\left(-4x\right)=30$

  $\Rightarrow 6x+4x=30$

  $\Rightarrow 10x=30$

  $\Rightarrow x=\frac{30}{10}=3$

Further, $y=-4x$

  $\Rightarrow y=-4\times 3=-12$

Thus, the solution of given system of equations is $x=3$ and $y=-12$ .

Conclusion:

The solution of given system of equations is $x=3$ and $y=-12$ .