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# Solve each system using substitution?

-7x+2y=18

6x+6y=0

### 5 Answers

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- cmcsafeLv 73 weeks agoBest Answer
{-7x+2y=18 ⇒ 2y=18+7x

{6x+6y=0 divide both sides by 3. 2x+2y=0

Substitute 2y from the first to the second

2x+(18+7x)=0

9x+18=0

9x=-18

x=-2

Put it into the second

6(-2)+6y=0 divide both sides by 6

-2+y=0

y=2

The unique solution is x=-2 & y=2

- Engr. RonaldLv 73 weeks ago
[-7x+2y=18 ]3

6x+6y=0

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-21x + 6y = 54

-[6x + 6y = 0]

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... - 27x = 54

x = -2 answer//

plug in x = - 2 to eq 2

6x+6y=0

6(-2) + 6y = 0

- 12 + 6y = 0

6y = 12

y = 2 answer//

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- Φ² = Φ+1Lv 73 weeks ago
6x+6y=0 means y = -x, so substitute y for -x in -7x+2y=18

9y=18, so y = 2 and x = -2

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