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How do I solve -4x+y=6 and -5x-y=21 with substitution

User Kathy Judd
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1 Answer

4 votes

Answer:

Explanation:

−4x+y=6 ------------ (1)

−5x−y=21 ----------- (2)

We can transpose −4x in the first equation to the right hand side:

y=4x+6 ------(3)

Substituting y from the third equation into the second one gives us:

−5x−(4x+6)=21

−5x−4x−6=21

−9x−6=21

−9x=21+6

−9x=27

x=27÷−9

x=−3

Substituting x=−3 in the third equation will give us :

y=4(−3)+6

y=−12+6

y=−6

The solution to both these equations : x=−3 ; y=−6

HOPE IT HELPS!

User Smallsense
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