Where are you stuck? You did the obvious subtraction, and... then what?I have a problem on -2x-9y=-25
-4x-9y=-23
Okay; you're wanting to add instead of subtract. That's fine. You multiplied one of the equations by -1 to create the opposite-sign terms and... then what?I have to eliminate the number that has the opposite sign
I have a problem on -2x-9y=-25
-4x-9y=-23
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FYI: In many ("most"?) books, this replacement, being a substitution, is called the method of substitution. "Elimination" means "setting up the equations so you can add down and eliminate one of the variables".Your question asked how to use elimination.
From the first equation get 9y = 25-2x
Then "eliminate" the 9y in the second equation, by replacing....
Oh, Yes,FYI: In many ("most"?) books, this replacement, being a substitution, is called the method of substitution. "Elimination" means "setting up the equations so you can add down and eliminate one of the variables".