Question 10 - MCQs from NCERT Exemplar - Chapter 2 Class 10 Polynomials

Transcript

Question 10 The zeroes of the quadratic polynomial x2 + kx + k, k ≠ 0, cannot both be positive (b) cannot both be negative (c) are always unequal (d) are always equal Let p(x) = x2 + kx + k If k is negative Sum is positive, product is negative ∴ One zero will be positive, one will be negative If k is positive Sum is negative but product is positive ∴ Both Zeroes are negative So, in both cases, both zeroes cannot be positive So, the correct answer is (A) Sum of Zeroes = (−𝒃)/𝒂 Sum of Zeroes = (−𝑘)/1 Sum of Zeroes = −k Product of Zeroes = 𝑪/𝑨 Product of Zeroes = k Product of Zeroes = k If k is positive Sum is negative but product is positive ∴ Both Zeroes are negative So, in both cases, both zeroes cannot be positive So, the correct answer is (A)