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2 years ago

What method would you choose to solve the equation 2x2 – 7 = 9? Explain why you chose this method.

2 answers:

8 0

Sample Response/Explanation: I would use the square root property of equality. Because there is no x term, I would just add and divide to get x2 by itself. Then I would take the square root.

oksano4ka [1.4K]2 years ago

7 0

I would add 7 to get ...

... 2x² = 16

then divide by 2 to get

... x² = 8

Now, I would take the square root, recognizing that both positive and negative values will solve the problem.

... x = ±√8

The root can be simplified, so we have ...

... x = ±2√2

_____

The above method seemed the most obvious method to me. One could use the quadratic formula, but that seems to involve more operations.

... 2x² -16 = 0 . . . . subtract 9

... x = (-0 ± √(0² -4·2·(-16)))/(2·2) . . . . put the coefficients into the formula

... x = ±(√128)/4 = ±√8 = ±2√2 . . . . . simplify the result

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2 years ago

PLEASE HELP ASAP: A particle is moving with velocity v(t) = t2 – 9t + 18 with distance, s measured in meters, left or right of z

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1) $\frac{v(8)-v(0)}{8 - 0} = \frac{10-18}{8} = -1\frac{m}{s}$ .
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2 years ago

A circular backyard pool has a diameter of 26 feet and is 4 feet deep. One cubic foot of water has a capacity of approximately 7

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Find the water volume of the pool. The formula for a vertical cylinder is V = pi*r^2*h, which here is V = pi(13 ft)^2*(4 ft) = 676*pi cubic feet.

Now convert this 676 cu. ft. to gallons:

Mult (676*pi cu ft) by the conversion factor (7.48 gal) / (1 cu ft):

676*pi cu ft 7.48 gal
--------------- * ------------- = 5056*pi gallons (rounded down from 5056.48 pi)
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The cost of filling the pool will be

5056.48*pi gallons $3
--------------------------- * ------------- = $48 (to the nearest dollar)
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