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# Elimination strategies

Practice identifying strategies for eliminating variables in a system of equations.

## Want to join the conversation?

• when will i use any of this in my life
• You won't know that until you find need to. But you won't find you need to if you don't know how.

Your life isn't a pre-planned route you follow, where one of the steps is using this elimination strategy.

Instead, learning something is like unlocking a door that you can then walk through. You might find other interesting doors behind that door that lead to nice places.

To think of it another way, imagine if you understood a foreign language that you don't. Think of all the people that only speak that language, all the books, TV programmes, podcasts, etc that have been made in that language. You'll never experience any of them unless you learn that language, and you'll probably never know that you're missing them.
• Also could you simplify the equations first?
• Yes,It can be simplified if all the terms in the equation are having a common factor.
For example-
4x - 2y = 8 can be simplified to 2x - y = 4
(By dividing by 2 because, 2 is their common factor)
• Could dividing the equations work?
• Determine the multiplier of the variable and divide both sides by it. Because the equation involves multiplying 20x, undo the multiplication in the equation by doing the opposite of multiplication, which is division. Divide each side by 20.
Reduce both sides of the equal sign. 20x ÷ 20 = x. 170 ÷ 20 = 8.5. x = 8.5.
• I still dont know how to do this
• you can use them to obtain new avatars and whatnot
• So, as long as you eliminate a variable, you can proceed to solving the equation?
• In the elimination method you either add or subtract the equations to get an equation in one variable. When the coefficients of one variable are opposites you add the equations to eliminate a variable and when the coefficients of one variable are equal you subtract the equations to eliminate a variable.
Set apart two of the equations and eliminate one variable. Set apart another two equations and eliminate the same variable. Repeat the elimination process with your two new equations. Solve the final equation for the variable that remains.
• At , why did Sal rule Choice A after the x's and the y's don't get eliminated? Wouldn't Sal subtract the numbers on the right side (7-7=0)? This would eliminate the variable on the right side!
• The numbers on the right are constants, as are the numbers in front of X and Y.

The variables are Xs and Ys themselves. They're called variables because we do not know their value - which can change or vary, depending on the situation/problem/question.
• I still dont understand