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3 years ago

For what values of K does x2+kx+9=0

Mathematics

1 answer:

Airida [17]3 years ago

4 0

Answer:

$k = 6$

Step-by-step explanation:

$x {}^{2} + kx + 9 = 0$

here,

a = 1,

b = k

c = 9

now,

$D = b {}^{2} - 4ac$

$k {}^{2} - 4(1)(9) = 0 \\ k {}^{2} - 36 = 0 \\ k {}^{2} = 36 \\ k = 6$

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Oliver and Lenny started hiking a hill simultaneously from the bottom to the top. Oliver hiked at a speed of 5 km/h during the f

Papessa [141]

Answer:

<u>Oliver and Lenny reached the top of the hill at the same time</u>

<u>The proportion of time Oliver spent hiking to that of Lenny is 1:1</u>

Step-by-step explanation:

1. Let's review the information given to us to answer the question correctly:

Oliver's speed = 5 km/h during the first half, then decreased his speed to 4 km/h during the second half.

Lenny's speed = 4 km/h during the first half, then increased his speed to 5 km/h in the second half.

2. Who reached the top of the hill first? What is the proportion of time he spent hiking to that of his friend?

Let's assume the distance from the bottom to the top of the hill is 10 kilometers for calculating the time it will take Oliver and Lenny to reach the top of the hill:

Speed = Distance/Time

Time = Distance/Speed

Oliver = Time of hiking first 5 km + Time of hiking second 5 km

Lenny = Time of hiking first 5 km + Time of hiking second 5 km

Oliver = 5/5 + 5/4

Oliver = 1 + 5/4 = 2 1/4 hours

Lenny = 5/4 + 5/5

Lenny = 5/4 + 1 = 2 1/4 hours

<u>Oliver and Lenny reached the top of the hill at the same time</u>

<u>The proportion of time Oliver spent hiking to that of Lenny is 1:1</u>

3 0

3 years ago

Write down the inequality described by "half of x is no more than six", and solve it<br>

Montano1993 [528]

X/.5 > 6
(the > has a line under it but idk how to type that lol)

5 0

3 years ago

The algebra tiles represent the perfect square trinomial x2 10x c. what is the value of c? c =

devlian [24]

The value of c for which the considered trinomial becomes perfect square trinomial is: 20 or -20

<h3>What are perfect squares trinomials?</h3>

They are those expressions which are found by squaring binomial expressions.

Since the given trinomials are with degree 2, thus, if they are perfect square, the binomial which was used to make them must be linear.

Let the binomial term was ax + b(a linear expression is always writable in this form where a and b are constants and m is a variable), then we will obtain:

$(ax + b)^2 = a^2x^2 + b^2 + 2abx$