Square of 3x - 4y is
(a) 9x² - 16y²
(b) 6x² - 8y²
(c) 9x² + 16y² + 24xy
(d) 9x² + 16y² - 24xy

Solution:

Correct answer is option (d)

Given, Square of 3x - 4y = (3x - 4y)²

Using the identity, (a - b)² = a² - 2ab + b²

Here, a = 3x and b = 4y

∴ (3x - 4y)² = (3x)² - 2(3x)(4y) + (4y)²

= 9x² - 24xy + 16y²

✦ Try This: Square of 5m - 2n is ______?

Given, Square of 5m - 2n = (5m - 2n)²

Using the identity, (a - b)² = a² - 2ab + b²

Here, a = 5m and b = 2n

∴ (5m - 2n)² = (5m)² - 2(5m)(2n) + (2n)²

= 25m² - 20mn + 4n²

☛ Also Check: NCERT Solutions for Class 8 Maths Chapter 9

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NCERT Exemplar Class 8 Maths Chapter 7 Problem 13

Square of 3x - 4y is (a) 9x² - 16y², (b) 6x² - 8y², (c) 9x² + 16y² + 24xy, (d) 9x² + 16y² - 24xy

Summary:

Square of 3x - 4y is 9x² + 16y² - 24xy

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☛ Related Questions:

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• Coefficient of y in the term -y/3 is (a) -1 (b) -3 (c) -1/3 (d) 1/3
• a² – b² is equal to (a) (a – b)² (b) (a – b) (a – b) (c) (a + b) (a – b) (d) (a + b) (a + b)