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3x + 9 y = 120

5x + 5y = 90

multiply first equation by 5 ( both sides)

multiply second equation by 3 ( both sides)

15 x + 45 y = 600

15 x + 15 y = 270

subtract

30y = 330

divide by 30

y = 11

substiute y into first equation

3 x + 9 y = 120

3x + 99 = 120

3x = 21

x = 7

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13y ago
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Q: How do you solve the simultaneous equation 3x plus 9y equals 120 5x plus 5y equals 90?
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