when two numbers have the same variable, we can add and subtract just like normal numbers.
12x + 8x = 20x - 3x = 17x
Answer:
x=13
Step-by-step explanation:
ok so let x+y=22
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x and y are the 2 unkown Number
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x-y=4
their difference is 4
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add both equations
(x+y=22)
+(x-y=4)
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y's cancel out
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2x=26
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x=13
Answer:
Associative
Step-by-step explanation:
Associative property is the one that says that when 3 or more numbers are summed, the grouping of such numbers has no effect on the result of the sum. It is:
(a + b) + c = a + (b + c) for every a, b and c real numbers.
<em>y</em> - 1/<em>z</em> = 1 ==> <em>y</em> = 1 + 1/<em>z</em>
<em>z</em> - 1/<em>x</em> = 1 ==> <em>z</em> = 1 + 1/<em>x</em>
==> <em>y</em> = 1 + 1/(1 + 1/<em>x</em>) = 1 + <em>x</em>/(<em>x</em> + 1) = (2<em>x</em> + 1)/(<em>x</em> + 1)
<em>x</em> - 1/<em>y</em> = <em>x</em> - (<em>x</em> + 1)/(2<em>x</em> + 1) = (2<em>x</em> ² - 1)/(2<em>x</em> + 1) = 1
==> 2<em>x</em> ² - 1 = 2<em>x</em> + 1
==> 2<em>x</em> ² - 2<em>x</em> - 2 = 0
==> <em>x</em> ² - <em>x</em> - 1 = 0
==> <em>x</em> = (1 ± √5)/2
If you start solving for <em>z</em>, then for <em>x</em>, then for <em>y</em>, you would get the same equation as above (with <em>y</em> in place of <em>x</em>), and the same thing happens if you solve for <em>x</em>, then <em>y</em>, then <em>z</em>. So it turns out that <em>x</em> = <em>y</em> = <em>z</em>.
