Answer:
<h2>12</h2>Step-by-step explanation:
To evaluate 4P2, we will use the permutation formula as shown;
nPr =
4P2 =
4P2 = 12
What is the length of EF in the right triangle below?
1 answer:
Answer:
A
Step-by-step explanation:
Since the triangle is right use Pythagoras' identity to find EF
The square on the hypotenuse is equal to the sum of the squares on the other two sides, that is
EF² + DF² = DE² ← substitute values
EF² + 12² = 18², that is
EF² + 144 = 324 ( subtract 144 from both sides )
EF² = 180 ( take the square root of both sides )
EF = → A
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Answer:
The three-digit numbers with these properties are 850 or 941.
Step-by-step explanation:
Let x be the hundreds digit, y the tens digit, and z the ones digit. The first condition says that . The second condition is:
the original number is while the reversed number is
so
Now we have the system
You can divide by 99 to simplify the second equation.
Note that x, y, z must be digits between 0 and 9 and . If
, then the second equation forces
, for example z=2 so x-2=8, x=10 which is impossible. If z=0, you get x=8, y=5 and the number is 850. If z=1, you get x=9,y=4 and the number is 941.