Explanation

Bravery is a quality or feeling that cannot be seen or touched—hence, it is an abstract noun.

Abstract nouns represent ideas, qualities, or states rather than physical objects.

Explanation

Given quadratic equation: 9x² - 27x + k = 0

Step 1: Find the sum and product of roots

Sum of roots (α + β) = -(-27)/9 = 3

Product of roots (αβ) = k/9

Step 2: Use the given condition

2α + 5β = 7

We also know α + β = 3

Step 3: Express α in terms of β or vice versa

From α + β = 3, α = 3 - β

Step 4: Substitute α in the given condition

2(3 - β) + 5β = 7

6 - 2β + 5β = 7

3β = 1

β = 1/3

Step 5: Find α

α = 3 - β = 3 - 1/3 = 8/3

Step 6: Find k using the product of roots

αβ = k/9

(8/3)(1/3) = k/9

8/9 = k/9

k = 8

Explanation

Jean Piaget proposed that as children grow, their schemes (mental representations) become more complex, abstract, and realistic through stages of cognitive development.

These stages include sensorimotor, preoperational, concrete operational, and formal operational stages.

Explanation

Custom means رواج

Habit means عادت

Explanation

To find the percentage:

(72 ÷ 360) × 100% ≈ 20%

So, 72 is approximately 20% of 360.

Explanation

Given sin θ > 0 and tan θ > 0:

Step 1: Determine the quadrants for sin θ > 0

sin θ > 0 in the 1st and 2nd quadrants.

Step 2: Determine the quadrants for tan θ > 0

tan θ > 0 in the 1st and 3rd quadrants.

Step 3: Find the common quadrant

The common quadrant where both conditions are met is the 1st quadrant.

Explanation

To determine the nature of the points A(3, 2), B(9, 10), and C(1, 16), let's calculate the distances between each pair of points.

Step 1: Calculate the distance AB

AB = √((9 - 3)² + (10 - 2)²)

= √(6² + 8²)

= √(36 + 64)

= √100

= 10

Step 2: Calculate the distance BC

BC = √((9 - 1)² + (10 - 16)²)

= √(8² + (-6)²)

= √(64 + 36)

= √100

= 10

Step 3: Calculate the distance AC

AC = √((3 - 1)² + (2 - 16)²)

= √(2² + (-14)²)

= √(4 + 196)

= √200

= 10√2

Step 4: Determine the nature of the points

Since AB = 10, BC = 10, and AC = 10√2, and AB = BC ≠ AC, the points form an isosceles triangle.

The answer is: The points form an isosceles triangle.

Explanation

Since P ∝ 1/V, it means P × V = constant.

So, 10 × 25 = P × 20

Solving:

250 = 20P ⇒ P = 12.5 N/m²

Explanation

Let's find the unknown value x using the proportion x : 5 :: 6 : 15.

We can set up the proportion as x/5 = 6/15.

Step 1: Cross-multiply

15x = 6 * 5

Step 2: Simplify

15x = 30

Step 3: Solve for x

x = 30 / 15

x = 2

Explanation

"Mine" is a possessive pronoun that shows ownership.

It replaces a noun phrase like "my car" to avoid repetition.