Ac method
for
ax^2+bx+c
multiply a and c together
find what 2 numbers multiply to get ac and add to get b
split b up
gropu
factor
3x^2+7x+2
2 times 3=6
what 2 numbers multily to get 6 and ad to get 7
6 and 1
3x^2+6x+1x+2
(3x^2+6x)+(1x+2)
3x(x+2)+1(x+2)
(3x+1)(x+2) is factored
The square root of -5
2.23606798
or
-2.23606798
Basically you need to find the answer choice that is rational. That way the sum will also be rational.
√7 is irrational as well as π and 0.5050050005...
2/4 is the only rational option.
answer: D
Answer:
- 8, 15, 17 — yes
- 15, 20, 25 — yes
- 20, 48, 52 — yes
- 2, 9, 11 — no
- 39, 80, 89 — yes
Step-by-step explanation:
The squares of the three numbers in each of the given triples are listed. When the sum of the first two numbers is equal to the third, the set of numbers in the triple is a Pythagorean triple.
{64, 225, 289}, yes
{225, 400, 625}, yes — a 3,4,5 triple multiplied by 5
{400, 2304, 2704}, yes — a 5,12,13 triple multiplied by 4
{4, 81, 121}, no*
{1521, 6400, 7921}, yes.
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* the smallest set of integers that is a Pythagorean triple is {3, 4, 5}. The number 2 in this group tells you this cannot be a PT.
