Joyce is trying to solve the equation y = x2 - 8x + 7 using the quadratic formula. She has made an error in one of the steps below. Find the step where Joyce went wrong. Step 1: x equals negative 8 plus or minus the square root of the quantity eight squared minus four times one times seven, end q Step 2: x equals negative 8 plus or minus the square root of sixty-four minus twenty-eight all over two times one. Step 3: x equals negative 8 plus or minus the square root of thirty-six all over two times one. Step 4: x equals negative 8 plus or minus six all over two.

Question

Mathematics

Cain

8 December, 19:02

Joyce is trying to solve the equation y = x2 - 8x + 7 using the quadratic formula. She has made an error in one of the steps below. Find the step where Joyce went wrong. Step 1: x equals negative 8 plus or minus the square root of the quantity eight squared minus four times one times seven, end q Step 2: x equals negative 8 plus or minus the square root of sixty-four minus twenty-eight all over two times one. Step 3: x equals negative 8 plus or minus the square root of thirty-six all over two times one. Step 4: x equals negative 8 plus or minus six all over two.

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Answers (2)

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Daphne Baxter · Answer 1

The error is in the first step. It should be (+8 plus or minus the square root of the quantity eight squared minus four times one times seven). This is because "b" is - 8 so - b is - (-8) = + 8

Cameron Forbes · Answer 2

Step 1

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