Ex 4.3, 2 (i) - Chapter 4 Class 10 Quadratic Equations

Transcript

Ex 4.3, 2 Find the values of k for each of the following quadratic equations, so that they have two equal roots. (i) 2x2 + kx + 3 = 0 2x2 + kx + 3 = 0 Comparing equation with ax2 + bx + c = 0 a = 2, b = k, c = 3 Since the equation has 2 equal roots, D = 0 b2 – 4ac = 0 Putting values k2 – 4×𝟐×𝟑=𝟎 k2 – 24 = 0 k2 = 24 k = ±√𝟐𝟒 k = ± √(6 ×4) k = ± √6 × √4 k = ± √6 × √(2^2 ) k = ± √6 × 2 k = ± 2√𝟔