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4 votes
15x 22x - 6) = 10x + 7
What is x?

User Daryl
by
4.8k points

1 Answer

5 votes

Answer:

x = 1/66 + sqrt(863/5)/66 or x = 1/66 - sqrt(863/5)/66

Explanation:

Solve for x:

330 x^2 - 6 = 10 x + 7

Subtract 10 x + 7 from both sides:

330 x^2 - 10 x - 13 = 0

Divide both sides by 330:

x^2 - x/33 - 13/330 = 0

Add 13/330 to both sides:

x^2 - x/33 = 13/330

Add 1/4356 to both sides:

x^2 - x/33 + 1/4356 = 863/21780

Write the left hand side as a square:

(x - 1/66)^2 = 863/21780

Take the square root of both sides:

x - 1/66 = sqrt(863/5)/66 or x - 1/66 = -sqrt(863/5)/66

Add 1/66 to both sides:

x = 1/66 + sqrt(863/5)/66 or x - 1/66 = -sqrt(863/5)/66

Add 1/66 to both sides:

Answer: x = 1/66 + sqrt(863/5)/66 or x = 1/66 - sqrt(863/5)/66

User Svarlitskiy
by
5.6k points