Question

5How many solutions does the system have?y = -3x + 93y = -9x + 9

Answer 1

Let:

y = -3x + 9 (1)

3y = -9x + 9 (2)

Replace (1) into (2)

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

Use distributive property on the left hand side:

-9x + 27 = -9x + 9

Add 9x to both sides:

-9x + 27 + 9x = -9x + 9 + 9x

27 = 9

This is false, because:

27≠9

therefore, the system doesn't have solutions

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