Math 10 – week 18 – elimination

In this week of Math 10 we learned about the Elimination method.

The first step is to find a zero pair.

If we use the example 3x+4y=2.5 and 5x-4y=25.5 the +4y and -4y cancel each other out. You then have 8x=28. To cancel out x you divide both sides by 8 and you get x=28/8 which turns into x=7/2. That’s your x value. To get the Y value you can substitute the x value which is 7/2 and substitute it for x in any of the equations. For this example I am going to choose the first equation. The first equation then become 3(7/2)+4y=5/2 (*2.5 is the same as 5/2). That equation turns into 21/2+4y=5/2. You then subtract 21/2 from both sides and you get 4y=-16/2 which is the same as 4y=-8. Now we divide both sides by 4 and you get y=-2. That is how you get your x and y values using elimination. Your coordinates are (7/2, -2)