Chapter ISG, Problem 6.4STP

To determine

To solve the system

Answer to Problem 6.4STP

  $x=2$ and $y=-5$ is the solution

Explanation of Solution

Given information:

  $\begin{array}{l}3x+2y=-4\\ -7x-2y=-4\end{array}$

Calculation:

Assume equation be (1) and (2) respectively

To solve equations by elimination, the given equations are either added or subtracted to get an equation in only one variable.

Let’s eliminate variable y here. To eliminate a variable, the coefficients of the variable must be same in both the equations.

Here, coefficients of y is same, now subtract (1) and (2)

  $3x+2y-7x-2y=-4-4$

Solving,

  $-4x=-8$

Dividing equation by -4

  $x=2$

Put value of x in (1)

  $-7(2)-2y=-4$

Solving,

  $-14-2y=-4$

so,

  $-2y=-4+14$

Dividing equation by -2,

  $y=-5$

Hence, $x=2$ and $y=-5$ is the solution of system