Answer:
B
Step-by-step explanation:
Given a quadratic equation in standard form
ax² + bx + c = 0 ( a ≠ 0 )
Then the discriminant is
Δ = b² - 4ac
• If b² - 4ac > 0 then 2 real irrational roots
• If b² - 4ac > 0 and a perfect square then 2 real rational roots
• If b² - 4ac = 0 then 1 real double root
• If b² - 4ac < 0 then 2 complex roots
Given
x² + 3x - 7 = 0 ← in standard form
with a = 1, b = 3, c = - 7 , then
b² - 4ac
= 3² - (4 × 1 × - 7) = 9 + 28 = 37
Since b² - 4ac > 0 then 2 real irrational roots
For a better understanding of the solution given here please find the attached file which has the relevant diagram.
To answer this question we will have to make use of <u>the Isosceles Triangle Theorem</u> which states that the perpendicular bisector of the base of an isosceles triangle is also the angle bisector of the vertex angle. Thus, as a corollary we know that is EF is the angle bisector of the vertex angle ∠E, then, EF is the perpendicular bisector of the of the base DK.
Please follow the diagram of a complete understanding of the logic and the solution.
As EF is the angle bisector as given in the question, thus we will have:
.
Also, from the Theorem we know that KF will be half of DK and thus, KF will be:
centimeters.
Likewise, from the same theorem we have: 
We have to know divide the total meters that has been traveled by the tortoise which is for 4.8 meters to the time it was completed which is 3 minutes. The formula for speed is: [ speed = distance/time ]. So the equation will be 4.8 meters/3 minutes = 1.6 meters per minute. The speed of the tortoise is 1.6 meters per minute.
9.56 because you don't round up when two is the next number. (The hundredths place is the second number after the decimal, where the 6 is in the original number.)
