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Algebra - Square Root Problem

by danny
(union)











































36x² - 81

Solve the following quadratic equation for the two values of x.

Do not use the quadratic formula.

Comments for Algebra - Square Root Problem

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Mar 23, 2011
Algebra - Square Root Problem
by: Staff

The question:

by Danny
(Union)

36x^2-81


The answer:

Although your submission does not have an equal sign, I presume you need to solve for x in the following equation:

36x² - 81 = 0

To solve this equation, begin by adding 81 to each side of the equation.

36x² - 81 + 81 = 0 + 81

36x² - 81 + 81 = 81

36x² + 0 = 81

36x² = 81

The next step is to take the square root of each side of the equation.

sqrt(36x²) = sqrt(81)

6x = 9

Divide each side of the equation by 6.

6x/6 = 9/6

x * (6/6) = 9/6

x * (1) = 9/6

x = 9/6

Reduce the fraction 9/6 to the lowest terms.

x = 9/6

x = (3*3)/(2*3)

x = (3/2)*(3/3)

x = (3/2)*(1)

x = 3/2 (or 1.5, if you prefer)

the final answer is: x = ±3/2



the last step: check the work. Substitute 3/2 for x in the original equation.

36x² - 81 = 0

36*x² - 81 = 0

36*(3/2)² - 81 = 0

36*(3/2)*(3/2) - 81 = 0

(36*3*3)/(2*2) - 81 = 0

(324/4) - 81 = 0

81 - 81 = 0

0 = 0

Since 0 does = 0, the solution for x is correct. x = 3/2.


Final note:

As you know, x^2 and x² stand for the same thing.

If you prefer, you can type x² using your keyboard as follows:

Type "x", then hold down the Alt key on your keyboard. While the Alt key is depressed, type 0178. Then release the alt key. The result will be:





Thanks for writing.


Staff
www.solving-math-problems.com


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