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Using the quadratic formula to solve 7x2 – x = 7, what are the values of x?

2 Answers

6 votes

Answer:

B!

Explanation:

Just took the test B==D

User Jughead
by
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5 votes
How the quadratic formula works:

For any quadratic equation ax² + bx + c = 0, the solution is
x=(-b\pm√(b^2-4ac))/(2a).

In the case of our equation 7x² - x = 7, first we need to subtract 7 from each side so that we have 0 on the right.
7x² - x - 7 = 0

Identify the values of a, b, and c.
a = 7, b = -1, and c = -7.

Plug these into our quadratic formula and solve.


x=(-(-1)\pm√((-1)^2-4(7)(-7)))/(2(7))=\boxed{(1\pm√(197))/(14)

There are two values for x: (1+√197)/14 and (1-√197)/14.
The approximate values for these are 1.073976 and -0.931119.
User Adam Meyer
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8.3k points