The last way to solve a system of linear equations is by elimination. You add the to equations, or combine. You will often need to multiply both sides of an equation so that when you combine the equations together, either x or y will be elimated. Once you find out what the variable you isolated is, substitute it in to one of the original equations and solve for the other variable. Write your answer as an ordered pair as always. Emma H. per 1
The Elimination Method (AKA Combinations) Today we used the elimination method. Our goal was to get rid of either x or y on the left side. In order to do that we had to add the first equation to the second. When we did that we ended up with a number multiplied either by x or y. Then, we had to get the variable alone, so we divided by the reciprocal. in the end, we had a variable equal to a number.
Ex.
X + Y = 5 (first equation)
2X -Y = 4 (second equation)
We have to add these two together.
X + Y = 5 (add them together) 2X -Y = 4 +___________ 3X + 0= 9 3X = 9 (1/3)3X = 9 (1/3)(get the variable alone) X = 3
Now plug three into the first equation to see if its true.
X + Y = 5
3 + Y = 5 (plugged the three in)
3 + Y = 5 (Get the y alone) -3 -3 ___________ Y = 2 (Y equals 2)
5 comments:
In class we learned about the third system of equations, the elimination method. For the third time, we went over the systems of two linear equations.
Lauren O.
Period 6
can anybody help me on number 11. it is really confusing. the second equation cancels out the x and y in the first equation. Help.
Alex D.
Period 3
alex we aren't doing # 11
The last way to solve a system of linear equations is by elimination. You add the to equations, or combine. You will often need to multiply both sides of an equation so that when you combine the equations together, either x or y will be elimated. Once you find out what the variable you isolated is, substitute it in to one of the original equations and solve for the other variable. Write your answer as an ordered pair as always.
Emma H.
per 1
The Elimination Method
(AKA Combinations)
Today we used the elimination method. Our goal was to get rid of either x or y on the left side. In order to do that we had to add the first equation to the second. When we did that we ended up with a number multiplied either by x or y. Then, we had to get the variable alone, so we divided by the reciprocal. in the end, we had a variable equal to a number.
Ex.
X + Y = 5 (first equation)
2X -Y = 4 (second equation)
We have to add these two together.
X + Y = 5 (add them together)
2X -Y = 4
+___________
3X + 0= 9
3X = 9
(1/3)3X = 9 (1/3)(get the variable alone)
X = 3
Now plug three into the first equation to see if its true.
X + Y = 5
3 + Y = 5 (plugged the three in)
3 + Y = 5 (Get the y alone)
-3 -3
___________
Y = 2 (Y equals 2)
3 + 2 = 5
Its correct!
Zoya Andrabi
Period 3
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