All of these sets meet the requirements of the triangle inequality. The sum of any two numbers in the set is greater than the third one. (You really only need to check that the sum of the smallest two is greater than the largest.)
It can help to resolve the numbers that are only indicated as to value.
√13 ≈ 3.606
2√10 ≈ 6.325
_____
Your comparisons can be ...
2 + 3 = 5 > 3.606 . . . is a triangle
5 + 5 = 10 > 6.325 . . . . . . is a triangle
5 + 12 = 17 > 15 . . . . . . . . is a triangle
Answer:
The number is 5
Step-by-step explanation:
Let x represent the number
Now let's break it down!
Sum of a number and 3 gives;
x + 3
This is then doubled to give;
2* (x + 3)
This is added to the product of 6 and the original number to give 46
Product of 6 and the original number = 6 * x
Now 2* (x + 3) is added to 6 * x to give 46
2* (x + 3) + 6*x = 46
2x + 6 + 6x = 46
8x + 6 = 46
Subtract 6 from both sides
8x + 6 - 6 = 46 - 6
8x = 40
x = 40/8
x = 5
Hence, the number is 5
I believe the phi ratio^2 = 1 + phi ratio
phi ratio = 1.6180339
phi ratio^2 = 2.6180339
11. Factoring and solving equations
- A. Factor-
1. Factor 3x2 + 6x if possible.
Look for monomial (single-term) factors first; 3 is a factor of both 3x2
and 6x and so is x . Factor them out to get
3x2 + 6x = 3(x2 + 2x1 = 3x(x+ 2) .
2. Factor x2 + x - 6 if possible.
Here we have no common monomial factors. To get the x2 term
we'll have the form (x +-)(x +-) . Since
(x+A)(x+B) = x2 + (A+B)x + AB ,
we need two numbers A and B whose sum is 1 and whose product is
-6 . Integer possibilities that will give a product of -6 are
-6 and 1, 6 and -1, -3 and 2, 3 and -2.
The only pair whose sum is 1 is (3 and -2) , so the factorization is
x2 + x - 6 = (x+3)(x-2) .
3. Factor 4x2 - 3x - 10 if possible.
Because of the 4x2 term the factored form wli be either
(4x+A)(x +B) or (2x+A)(2x+B) . Because of the -10 the integer possibilities
for the pair A, B are
10 and -1 , -10 and 1 , 5 and -2 . -5 and 2 , plus each of
these in reversed order.
Check the various possibilities by trial and error. It may help to write
out the expansions
(4x + A)(x+ B) = 4x2 + (4B+A)x + A8
1 trying to get -3 here
(2x+A)(2x+B) = 4x2 + (2B+ 2A)x + AB
Trial and error gives the factorization 4x2 - 3x - 10 - (4x+5)(x- 2) .
4. Difference of two squares. Since (A + B)(A - B) = - B~ , any
expression of the form A' - B' can be factored. Note that A and B
might be anything at all.
Examples: 9x2 - 16 = (3x1' - 4' = (3x +4)(3x - 4)
x2 - 29 = x2 - (my)* = (x+ JTy)(x- my)
Answer:
Step-by-step explanation:
1-2(2x+1)=1-(x-1)
-1(2x+1)=1-(x-1)
-2x-1=1-x-1
-2x+x=0+1
-x=1
x=-1
