Question

Explain the whole sum guys I can’t understand in this (class 10,quadratic)

Answer 1

Equation = x² + 4x + k = 0

On comparing with standard form of quadratic equation ( i.e., ax² + bx + c = 0 ) , We get

a = 1 ; b = 4 ; c = k

We know,

For real and distinct roots discriminant muts be greater than 0;

Discriminant, D = b² - 4ac

So,

☛ b² - 4ac > 0

☛ 4² - 4(k)(1) > 0

☛ 16 - 4k > 0

☛ -4k > -16

☛ 4k > 16

☛ k > 4

Hence, Option - (b) is correct.