Given the quadratic equation $x^{2} + a x + b = (x - 9) (x + 9)$ , find the value of $a b$ .

- 81

No worries! We‘ve got your back. Try BYJU‘S free classes today!

0

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

81

No worries! We‘ve got your back. Try BYJU‘S free classes today!

1458

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Open in App

Solution

The correct option is B $0$
Given, $x^{2} + a x + b = (x - 9) (x + 9)$
$\Rightarrow x^{2} + a x + b = x^{2} - 9 x + 9 x - 81$
$\Rightarrow x^{2} + a x + b = x^{2} - 81$
$∴ a = 0, b = - 81$
Then $a b = 0 \times - 81 = 0$

Suggest Corrections

Similar questions

x^{2} - 81 = 0

x^{2} - 4 x - {log}_{3} a = 0

a

4 x^{2} + 9 + 12 x = 81

x^{2} - 18 x + 81 = 0

81 x^{2} + k x + 256 = 0

k

Join BYJU'S Learning Program