Answer: C
<u>Step-by-step explanation:</u>
Replace x with 
and solve.
f(x) = 3x² - 6x - 1
f() = 3()² - 6() - 1
= 3(
) + 4 - 1
= 
+ 3
= + 
= 
To solve this problem you must apply the proccedure shown below:
1- The ladder forms an isosceles triangle, because it has two equal sides.
2- Let's call the angle 
. To calculate it , you can divide the triangle into two equal right triangles and the angle will be divided into two equal parts too. Therefore, you can calculate the half of the angle and then multiply it by two, as following:
The answer is: 
Answer:
triangle d
Step-by-step explanation:
it seems as though the others are right triangles are close to it, except for d
Answer:
yes
Step-by-step explanation:
The side lengths satisfy the Pythagorean theorem, so the triangle is a right triangle.
7.5² +10² = 12.5²
56.25 +100 = 156.25
_____
You may recognize that the ratios of side lengths are ...
7.5 : 10 : 12.5 = 3 : 4 : 5
A 3-4-5 triangle is a well-known right triangle, as this is the smallest set of integers that satisfy the Pythagorean theorem. They also happen to be consecutive integers, so form an arithmetic sequence. Any arithmetic sequence that satisfies the Pythagorean theorem will have these ratios.
_____
If you're familiar with trigonometry, you know the law of cosines tells you ...
c² = a² + b² - 2ab·cos(θ) . . . . where θ is the angle between sides a and b. This reduces to the Pythagorean theorem when θ=90°, which makes cos(θ)=0. If the sides do not satisfy the Pythagorean theorem, cos(θ)≠0 and the triangle is not a right triangle.
