Question

2 Find the value of discriminant
(1) x²+ 7x - 1 = 0
(2) 2y²- 5y + 10 =0​

Answer 1

x2 +7 x – 1 = 0  Comparing the above equation with ax2 + bx + c = 0, we get  a = 1, b = 7, c = -1  ∴ b2 – 4ac = (7)2 – 4 × 1 × (-1)  = 49 + 4  ∴ b2 – 4ac = 53 ii. 2y2 – 5y + 10 = 0  Comparing the above equation with ay2 + by + c = 0, we get  a = 2, b = -5, c = 10  ∴ b2 – 4ac = (-5)2 -4 × 2 × 10  = 25 – 80  ∴ b2 – 4ac = -55 iii. √2 x2 + 4x + 2√2 = 0  Comparing the above equation with ax + bx + c = 0, we get  a = √2,b = 4, c = 2√2  ∴ b2 – 4ac = (4)2 – 4 × √2 × 2√2  = 16 – 16  ∴ b2 – 4ac=0i. x2