Solving+systems+by+linear+substitution

John, Steven, Austin, Ryan, Mr. Sweeny Solving linear systems by substituiton is the way to find out when two or more things at one point intercept and become the same value.

The problem is finished when you get Y= ... X= ...

Step 1 get either x or y in either equation by itself. ex. 5x + 2y = 9 x + y = -3 You want to get the easier letter by itself which would be positive x or y. You get to choose. I will choose posititve y. So to get it by itself you must subtract 3x which will move it two the other side.

You will get y= - 3 - x

Step 2 Substitute. This is when you replace either the y or the x that you got by itself in either equation and move it into the other equation where x or y you did't is and replace the letter that you solved for in the other equation and replace it.. 5x 2( -3 -x) = 9. I substituted and if before you subsitute y it has a value then you multiply.

5x -6 -2x = 9 Step 3 combine like terms 5x -2x = 3x -6 = 9

Step 4 Get the letter by itself. 3x -6 = 9 ................................................ +6 + 6 You get 3x= 15 Then divide x= 5 .............................. You think were done? Well were not. You stil have to get a value for Y.

Step 5 substitute again. This time take x= 5 and put it into the part of the equation where you got y by itself. y= -3 - x which will become y= -3 - 5 Do the math and you get y= -8

Answer: (5,-8) Now you are done.

SEE THE ANSWERS BELOW!! ANSWERS:   1) Y = 2

2) -2, 2 