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anonymous
 one year ago
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 quantity, all over two times one.
Step 2: x equals negative 8 plus or minus the square root of sixtyfour minus twentyeight all over two times one.
Step 3: x equals negative 8 plus or minus the square root of thirtysix all over two times one.
Step 4: x equals negative 8 plus or minus six all over
anonymous
 one year ago
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 quantity, all over two times one. Step 2: x equals negative 8 plus or minus the square root of sixtyfour minus twentyeight all over two times one. Step 3: x equals negative 8 plus or minus the square root of thirtysix all over two times one. Step 4: x equals negative 8 plus or minus six all over

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anikhalder
 one year ago
Best ResponseYou've already chosen the best response.0So, let's go through this. Do you know the quadratic formula and how you can use it to solve this equation?

anikhalder
 one year ago
Best ResponseYou've already chosen the best response.0No problem, it goes like this: for an equation: \[ax ^{2}+bx+c = 0\] You can solve for x using the following formula (quadratic formula): \[x = \frac{ b \pm \sqrt{b^{2}4ac} }{ 2a}\] Hence, in the given equation y = x2 − 8x + 7 and when you set it to zero, i.e. \[x ^{2}− 8x + 7 = 0\] Then our a, b and c are as follows: a = 1 b = 8 c = 7 Now, just plug these into the quadratic formula and see which one out of the options you have is not satisfied. :)))

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Whoa that's a lot of letters Dx I'm sorry, I'm not exactly smart when it comes to these things

anikhalder
 one year ago
Best ResponseYou've already chosen the best response.0https://www.khanacademy.org/math/algebra/quadratics/quadraticformula/v/usingthequadraticformula Try this video :))) Much better than my explanation :P

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0Wait wait wait never mind! I think I got it now :)

Jacob902
 one year ago
Best ResponseYou've already chosen the best response.0Joyce 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 quantity, all over two times one. Step 2: x equals negative 8 plus or minus the square root of sixtyfour minus twentyeight all over two times one. Step 3: x equals negative 8 plus or minus the square root of thirtysix all over two times one. Step 4: x equals negative 8 plus or minus six all over two. Step 1 Step 2 Step 3 Step 4

Jacob902
 one year ago
Best ResponseYou've already chosen the best response.0Joyce 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. FIRST OF ALL, Y MUST EQUAL 0 Step 1: x equals negative 8 plus or minus the square root of the quantity eight squared minus four times one times seven, end quantity, all over two times one. THIS IS WRONG. IT SHOULD BE POSITIVE 8 plus or minus the square root of the quantity eight squared minus four times one times seven, end quantity, all over two times one. Step 2: x equals POSITIVE 8 plus or minus the square root of sixtyfour minus twentyeight all over two times one. Step 3: x equals POSITIVE 8 plus or minus the square root of thirtysix all over two times one. Step 4: x equals POSITIVE 8 plus or minus six all over two. Step 5 X=(8±6)/2 Step 6 X=14/2 =7 or Step 7 X=2/2 =1 Answers {1,7}
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