Explanation

If y ∝ 1/(x²) and y = 18 when x = 3, then y = 4.5 when x = 6

Solution:

Since y is inversely proportional to x², we can write  

y = k / x², where k is a constant.

When y = 18 and x = 3,

18 = k / 3²

18 = k / 9

k = 18 * 9 = 162

Now put k = 162 and x = 6 to find y,

y = 162 / 6²

y = 162 / 36

y = 4.5

So y = 4.5 when x = 6

Last verified on 24-05-2026

Explanation

Solve: (2x - 1)/3 = (x + 5)/2

Solution:

Step 1: Remove the denominators by cross multiplication

(2x - 1) _ 2 = (x + 5) _ 3

Step 2: Multiply out both sides

4x - 2 = 3x + 15

Step 3: Bring terms with x to left side and constants to right side

4x - 3x = 15 + 2

Step 4: Simplify

x = 17

Last verified on 24-05-2026

Explanation

If roots of x² - 9x + 20 = 0 are increased by 1, the new equation is x² - 11x + 30 = 0

Solution:

Step 1: Find the roots of x² - 9x + 20 = 0

Factorize:

x² - 9x + 20 = 0

x² - 5x - 4x + 20 = 0

x(x - 5) - 4(x - 5) = 0

(x - 4)(x - 5) = 0

So the roots are x = 4 and x = 5

Step 2: Increase each root by 1

New roots = 4 + 1 = 5 and 5 + 1 = 6

Step 3: Form the new equation

If roots are α and β, then equation is x² - (α + β)x + αβ = 0

Here α = 5, β = 6

Sum of roots = 5 + 6 = 11

Product of roots = 5 * 6 = 30

Therefore, new equation is:

x² - 11x + 30 = 0

Last verified on 24-05-2026

Explanation

If x² - px + 72 has factors differing by 1, then p = ±17

Solution in older version:

Let the two factors be m and m+1. 

Then,

x² - px + 72 = (x - m)(x - (m+1))

             = (x - m)(x - m - 1)

             = x² - (2m + 1)x + m(m+1)

Compare with x² - px + 72:

1. m(m+1) = 72

2. p = 2m + 1

Solve m(m+1) = 72:

m² + m - 72 = 0

(m + 9)(m - 8) = 0

So m = 8 or m = -9

Case 1: m = 8

Factors are 8 and 9

p = 2_8 + 1 = 17

Case 2: m = -9  

Factors are -9 and -8

p = 2_(-9) + 1 = -17

Last verified on 24-05-2026

Explanation

(a + bi)(a - bi) is the product of conjugates.  

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

Since i² = -1:  

= a² - b²(-1) = a² + b²  

Given (a + bi)(a - bi) = 61,  

so a² + b² = 61.

Last verified on 24-05-2026

Explanation

Given:  

a/b = 9/10  

b/c = 5/6  

Multiply both equations:  

(a/b) × (b/c) = (9/10) × (5/6)  

a/c = 45/60  

a/c = 3/4  

So a:c = 3:4.

Last verified on 23-05-2026

Explanation

Mean = (Sum of numbers) / (Total numbers)  

= (10 + 12 + 14) / 3  

= 36 / 3  

= 12  

Last verified on 23-05-2026

Explanation

• A secant is a line that cuts a circle and intersects it at exactly 2 distinct points.
• If it touches at 1 point, it’s a tangent.

Last verified on 23-05-2026

Explanation

cotθ = 1/tanθ  

So:  

cotθ × tanθ = (1/tanθ) × tanθ = 1  

Last verified on 23-05-2026

Explanation

Given:  

cos θ = 9/41  

Use the formula:  

sin²θ + cos²θ = 1  

Step 1: Put cos θ value  

sin²θ + (9/41)² = 1  

sin²θ + 81/1681 = 1  

Step 2: Find sin²θ  

sin²θ = 1 - 81/1681  

sin²θ = 1681/1681 - 81/1681  

sin²θ = 1600/1681  

Step 3: Take square root  

sin θ = ±√(1600/1681)  

sin θ = ±40/41  

Last verified on 23-05-2026