Problem

|연립방정식의 해의 개수와 그래프의 위치관계 | 정답률 $63 \%$
78 다음 일차함수의 그래프 중 일차함수 $y=-4 x+8$ 의 그래프와 교점이 무수히 많이 생기는 경우는?
(1) $4 x-8-y=0$
(2) $4 x-y+8=0$
(3) $y-4 x-8=0$
(4) $y+4 x-8=0$
(5) $y+4 x+8=0$

Answer

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Answer

\(\boxed{\text{Final Answer: (4) } y + 4x - 8 = 0}\)

Steps

Step 1 :Given the equation \(y = -4x + 8\), we need to find the equation that has infinitely many intersection points with it.

Step 2 :Check each option:

Step 3 :(1) \(4x - y - 8 = 0\) has the solution \(x = 2, y = 0\), which is not the same as the given equation.

Step 4 :(2) \(4x - y + 8 = 0\) has the solution \(x = 0, y = 8\), which is not the same as the given equation.

Step 5 :(3) \(y - 4x - 8 = 0\) has the solution \(x = 0, y = 8\), which is not the same as the given equation.

Step 6 :(4) \(y + 4x - 8 = 0\) has the solution \(x = 2 - \frac{y}{4}\), which has infinitely many intersection points with the given equation.

Step 7 :(5) \(y + 4x + 8 = 0\) has no solution.

Step 8 :\(\boxed{\text{Final Answer: (4) } y + 4x - 8 = 0}\)

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