Question

2 x² - 1 = 49

Answer 1

2x² - 1 = 49

=> 2x² = 50

=> x² = 25

=> x² = 5²

=>  x = 5

Vậy...

Answer 2

2x²-1=49

=>2x²=49+1

=>x²=50:2=25

=>x=-5;5

Answer 3

2x²-1=49

2x²=49+1=50

x²=50:2=25

x²=5²

=> x=5