Polynomials - Quantitative Aptitude Questions Page-3

17) (a + b)(a - b) =
(A) a(a - b) - b(a - b)
(B) a(b - a) + b(a - b)
(C) a(a + b) - b(b + a)
(D) a(a - b) + b(b - a)

Answer: Option C

Solution:
If we multiply (a + b) by (a - b), we proceed as a(a + b) - b(a + b) so option C is the correct answer

18) The sum of the polynomials, 6x² + 9x - 8 and 2x² - 5x + 3 is:
(A) 4x² - 14 x - 5
(B) 8x² + 14 x + 11
(C) 8x² - 4 x + 5
(D) 8x² + 4 x - 5

Answer: Option D

Solution:
(6x² + 9x - 8) + (2x² - 5x + 3)
= (6x² + 2x²) + (9x - 5x) + (-8 + 3)
= 8x²+ 4x - 5

19) (6x² + 9x - 8) - (4x² - 5x + 3) = ?
(A) 2x² - 14x - 11
(B) 2x² + 14x - 11
(C) 10x² + 4x - 11
(D) 10x² - 14x - 11

Answer: Option B

Solution:
(6x² + 9x - 8) - (4x² - 5x + 3)
= (6x² - 4x²) + (9x - (-5x)) + (-8 - 3)
= 2x²+ (9x + 5x) + (-11)
= 2x² + 14x - 11