Question

! 92 The roots of the quadratic equation 4x2 − 81 = 0 are

Answer 1

Answer:

4x²-81 = 0

(2x)²-9² = 0

(2x+9) (2x-9) = 0

x = -9/2 , x = 9/2

Answer 2

$4 {x}^{2} - 81 = 0 \\ 4 {x}^{2} = 81 \\ {x}^{2} = \frac{81}{4} \\ \\ x = \sqrt{ \frac{81}{4} } \\ \\ x = \frac{9}{2} \\ x = 4.5$

hope it helps