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State T for and F for false. (i) a ^(3...

State T for and F for false.
(i) `a ^(3) - b ^(3) = (a - b) ^(3)` if ab = 0
(ii) `(x + (1)/(x)) ^( 2) - (x - (1)/(x)) ^(2) = 2`
(iii) The remainder when `15 ^(2) - 26 x + 8` is divided by `3x - 4` is 1.

A

`{:(""(i), (ii), (iii)),(T, F, T):}`

B

`{:(""(i), (ii), (iii)),(T,T,F):}`

C

`{:(""(i), (ii), (iii)),(F,T,T):}`

D

`{:(""(i), (ii), (iii)),(T,F,F):}`

Text Solution

AI Generated Solution

The correct Answer is:
Let's solve each part of the question step by step. ### (i) \( a^3 - b^3 = (a - b)^3 \) if \( ab = 0 \) **Step 1:** Recall the identity for the difference of cubes: \[ a^3 - b^3 = (a - b)(a^2 + ab + b^2) \] **Step 2:** If \( ab = 0 \), then either \( a = 0 \) or \( b = 0 \). **Step 3:** Substitute \( ab = 0 \) into the identity: - If \( a = 0 \), then \( a^3 - b^3 = -b^3 \) and \( (a - b)^3 = (-b)^3 = -b^3 \). - If \( b = 0 \), then \( a^3 - b^3 = a^3 \) and \( (a - b)^3 = a^3 \). **Conclusion:** In both cases, \( a^3 - b^3 = (a - b)^3 \) holds true when \( ab = 0 \). **Final Answer:** True (T) ### (ii) \( (x + \frac{1}{x})^2 - (x - \frac{1}{x})^2 = 2 \) **Step 1:** Expand both squares: \[ (x + \frac{1}{x})^2 = x^2 + 2 + \frac{1}{x^2} \] \[ (x - \frac{1}{x})^2 = x^2 - 2 + \frac{1}{x^2} \] **Step 2:** Now subtract the second expression from the first: \[ (x^2 + 2 + \frac{1}{x^2}) - (x^2 - 2 + \frac{1}{x^2}) = 2 + 2 = 4 \] **Conclusion:** The left-hand side simplifies to 4, not 2. **Final Answer:** False (F) ### (iii) The remainder when \( 15^2 - 26x + 8 \) is divided by \( 3x - 4 \) is 1. **Step 1:** First, calculate \( 15^2 - 26x + 8 \): \[ 15^2 = 225 \quad \text{so} \quad 225 - 26x + 8 = 233 - 26x \] **Step 2:** To find the remainder when dividing by \( 3x - 4 \), we can use the Remainder Theorem. Set \( 3x - 4 = 0 \) to find \( x \): \[ 3x = 4 \quad \Rightarrow \quad x = \frac{4}{3} \] **Step 3:** Substitute \( x = \frac{4}{3} \) into \( 233 - 26x \): \[ 233 - 26 \left(\frac{4}{3}\right) = 233 - \frac{104}{3} \] Convert 233 to a fraction: \[ 233 = \frac{699}{3} \quad \Rightarrow \quad \frac{699}{3} - \frac{104}{3} = \frac{595}{3} \] **Step 4:** Check if \( \frac{595}{3} = 1 \): \[ \frac{595}{3} \neq 1 \] **Conclusion:** The remainder is not equal to 1. **Final Answer:** False (F) ### Summary of Answers: (i) True (T) (ii) False (F) (iii) False (F)
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