Let <em>n</em> be the unknown number. We can write it as
<em>n</em> = 10<em>a</em> + <em>b</em>
with <em>a</em> and <em>b</em> integers between 1 and 9 (either with positive or negative sign).
Reversing the digits gives another number
<em>m</em> = 10<em>b</em> + <em>a</em>
The first number is increased by 54 when the digits are reversed, which means
<em>m</em> = <em>n</em> + 54 → 10<em>b</em> + <em>a</em> = 10<em>a</em> + <em>b</em> + 54 → 9<em>b</em> - 9<em>a</em> = 54 → <em>b</em> - <em>a</em> = 6
The digit in the tens place of <em>n</em> is 3 times the digit in the ones place, so
<em>a</em> = 3<em>b</em>
Substitute this into the previous equation and solve for <em>b</em> :
<em>b</em> - <em>a</em> = <em>b</em> - 3<em>b</em> = -2<em>b</em> = 6 → <em>b</em> = -3
Solve for <em>a</em> :
<em>a</em> = 3<em>b</em> = 3(-3) = -9
Then the original number is <em>n</em> = 10<em>a</em> + <em>b</em> = 10(-9) + (-3) = -93
<span>P(n,2)=42, find n.
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n!/(n-2)! = 42
n(n-1) = 42
n^2 -n - 42 = 0
(n-7)(n+6) = 0
Positive answer:
n = 7
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Cheers,
</span>
i cant draw a triangle from a comput
You said that 8c + 5 = 4c - 11
Subtract 4c from each side: 4c + 5 = - 11
Subtract 5 from each side: 4c = - 16
Divide each side by 4 : c = - 4
