Question

x2+9x+20 is a quadratic polynomial whose zeroes are -4and -5 (true or false)?

Answer 1

Answer:

» x² + 9x + 20 = 0

» (x + 5) (x + 4) = 0

» x = -5 or -4

Hence, True.

Answer 2

Given:

The given quadratic equation is

⇒x²+9x+20=0

• The zeroes of given quadratic equation is -4 and -5

To Find :

• The statement is true or false :

Formula :

Determinant Method :

$\bullet \boxed{ \tt{ \delta = {b}^{2} - 4ac}}$

Formula Method :

$\bullet \boxed{ \tt{ x= \frac{ - b \pm \sqrt{ {b}^{2} - 4ac } }{2a} }}$

Solution :

•The given quadratic equation is x²+9x+20=0

$\implies \bf \: {x}^{2} + 9x + 20 = 0$

$\implies \sf \: {x}^{2} +5x + 4x + 20 = 0$

$\implies \sf \: x(x + 5) + 4(x + 5) = 0$

$\implies \sf \: (x + 5)(x + 4) = 0$

$\implies \sf \:x = - 5 \: or \: x = - 4$

The given statement is True

The given quadratic equation has 2 roots -5 and -4