Question 939459

-3x+7y=-16
-9x+5y+16

Part A: Create an equivalent system of equations by replacing one equation with the sum of that equation and a multiple of the other. Show the steps to do this.

Part B: Show that the equivalent system has the same solution as the original system of equations.
<pre>
- 3x + 7y = - 16 -------- eq (i)
- 9x + 5y =   16 -------- eq (ii)
Is the 2<sup>nd</sup> plus sign in the 2<sup>nd</sup> equation supposed to be "="? If so, then the most convenient method is to:
1) Multiply eq (i) by - 3, creating eq (iii)
2) Sum eqs (iii) &  (ii), thus eliminating x
3) Determine the value of y.