3x+6y=21 and 5x+8y=31 what does x and y equal

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3x+6y=21 and 5x+8y=31 what does x and y equal

1. (3x + 6y) / 3 = 21 / 3
2. x + 2y = 7
3. x = -2y + 7

4. 5 * (-2y + 7) + 8y = 31
5. -10y + 35 + 8y = 31
6. -2y = -4
7. y = 2     <<<<<

Substitute the value of y from equation 7 into equation 3.

x = -2 * 2 + 7 = -4 + 7 = 3   <<<<<

Going back to the original equations:

3x+6y=21       3 * 3 + 6 * 2 = 9 + 12 = 21
5x+8y=31       5 * 3 + 8 * 2 = 15 + 16 = 31
by Level 11 User (78.4k points)

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