Explanation

y ∝ 1/x → y = k/x  

When x = 3, y = 15:  

15 = k/3 → k = 45  

So y = 45/x  

When y = 5:  

5 = 45/x → x = 45/5 = 9  

Last verified on 07-05-2026

Explanation

(x + 2)/(x - 2) = 2, x ≠ 2

x + 2 = 2(x - 2)  

x + 2 = 2x - 4  

2 + 4 = 2x - x  

6 = x  

Last verified on 07-05-2026

Explanation

Original: x² - 4x + 3 = 0  

Roots: x = 1, x = 3

Square the roots: 1² = 1, 3² = 9

New equation with roots 1 and 9:  

(x - 1)(x - 9) = x² - 10x + 9 = 0  

Last verified on 07-05-2026

Explanation

Let roots be α and β. For x² - px + 20:  

Sum = α + β = p  

Product = αβ = 20  

Given: |α - β| = 1  

Use (α + β)² = (α - β)² + 4αβ  

p² = 1² + 4(20) = 1 + 80 = 81  

p = ±9  

Last verified on 07-05-2026

Explanation

(a + bi)(a - bi) = a² - (bi)² = a² - b²i² = a² + b²  

Given: a² + b² = 13  

Last verified on 07-05-2026

Explanation

a : b = 2 : 3

b : c = 3 : 4

Since the value for b is 3 in both, just chain them:  

a : b : c = 2 : 3 : 4

Last verified on 06-05-2026

Explanation

Data is already ordered: 1, 3, 5, 7, 9  

n = 5, which is odd  

Median = middle value = 3rd term = 5  

Last verified on 06-05-2026

Explanation

• An angle inscribed in a semicircle is always 90° due to the Thales' Theorem.
• It is called a right angle because the angle subtended by a diameter is always right.

Last verified on 06-05-2026

Explanation

sinθ = cosθ → tanθ = 1  

θ = 45° + 180°k  

Principal value: θ = 45°

Last verified on 06-05-2026

Explanation

tan θ = 1 when θ = 45° + 180°k  

Principal value: θ = 45°  

Last verified on 06-05-2026