Answer :
Answer:
x = 9 or x = -9
Step-by-step explanation:
x² - 4 = 77
then
x² - 4 + 4 = 77 + 4
then
x² = 81
then
x² - 81 = 0
then
x² - 9² = 0
then
(x - 9)(x + 9) = 0
then
x - 9 = 0 or x + 9 = 0
then
x = 9 or x = -9
__________________________
:)
Answer:
x = 9 or x = -9
Step-by-step explanation:
x² - 4 = 77
then
x² - 4 + 4 = 77 + 4
then
x² = 81
then
x² - 81 = 0
then
x² - 9² = 0
then
(x - 9)(x + 9) = 0
then
x - 9 = 0 or x + 9 = 0
then
x = 9 or x = -9
__________________________
:)