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-4x+4y=4 and under it is y=3x+9 freshman algebra

User Chidiebere
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1 Answer

4 votes

Answer:

x = -4

y = -3

Explanation:

-4x + 4y = 4 Eq. 1

y = 3x + 9 Eq. 2

Replacing Eq. 2 in Eq. 1:

-4x + 4(3x+9) = 4

-4x + (4*3x + 4*9) = 4

-4x + (12x+ 36) = 4

8x + 36 = 4

8x = 4 - 36

8x = -32

x = -32/8

x = -4

From Eq. 2

y = 3*-4 + 9

y = -12 + 9

y = -3

Check:

From Eq. 1

-4x + 4y = 4

-4*-4 + 4*-3 = 4

16 - 12 = 4

User Pavel Nuzhdin
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7.8k points