Answer:
the answer is the first one [3 -12 15 -21]
Step-by-step explanation:
Because 3 times 1 = 3, 3 times -4 = -12, 3 times 5=15, 3 times 7 = -21
because they are in order to get a negative one of them have to be a negative if they both of them where negative it would be positive.
Can you mark me brainliest
If there are 13 letters typed, the probability that no letters will be repeated can be found to be 1.05 x 10⁻²⁰
<h3>How to find the probability no letters are repeated?</h3>
First, find the number of possibilities of 13 letters from 26 letters in the alphabet as:
= 26 x 26 x 26 x 26 x 26 x 26 x 26 x 26 x 26 x 26 x 26 x 26 x 26
= 6.156 x 10³⁶ possibilities
If the numbers are not to be repeated then the possibilities are:
= 26 x 25 x 24 x 23 x 22 x 21 x 20 x 19 x 18 x 17 x 16 x 15 x 14
= 64764752532480000 possibilities
The probability that no letters are repeated is:
= 64764752532480000 / 6.156 x 10³⁶
= 0.0000000000000000000105
= 1.05 x 10⁻²⁰
Find out more on probability at brainly.com/question/8994028
#SPJ1

Let's do the bracket part first,
and solve further as shown,
Let x represent the larger number.
1/(x -28) +4/x = 1/6
Multiplying by the product of denominators, we have
6x +24(x -28) = x(x -28)
In standard form, this is
x^2 -58x +672 = 0
(x -42)(x -16) = 0
The two numbers are (-12 and 16) or (14 and 42).